cleanup: remove pointee types

This can't be merged until the oldest LLVM version we support uses opaque pointers, which will be the case after rust-lang#114148. (Also note `-Cllvm-args="-opaque-pointers=0"` can technically be used in LLVM 15, though I don't think we should support that configuration.)

I initially hoped this would provide some minor perf win, but in rust-lang#105412 (comment) it had very little impact, so this is only valuable as a cleanup.

As a followup, this will enable rust-lang#96242 to be resolved.

r? `@ghost`

`@rustbot` label S-blocked

…nest, r=Mark-Simulacrum

Nest other codegen test topics

This PR is like rust-lang#114229 in that it mostly pushes codegen tests around, shoving them into their own directories, but because all of the changes are very simple cleanups I pulled them into a separate PR. The other PR might involve actually evaluating the correctness of the test after changes, but here it is mostly a matter of taste. The only "functional" change is deleting a few tests that... hinge on a version of LLVM that we don't support (as of rust-lang#114148 anyways).

I considered a few different ways to group other topics but I feel the question of whether `tests/codegen/{vec,array,slice}` should exist is more subtle than these choices, as it might be better to group such related tests by other topics like bounds check elision, thus I avoided making it.

…ark-Simulacrum

Nest other codegen test topics

This PR is like rust-lang/rust#114229 in that it mostly pushes codegen tests around, shoving them into their own directories, but because all of the changes are very simple cleanups I pulled them into a separate PR. The other PR might involve actually evaluating the correctness of the test after changes, but here it is mostly a matter of taste. The only "functional" change is deleting a few tests that... hinge on a version of LLVM that we don't support (as of rust-lang/rust#114148 anyways).

I considered a few different ways to group other topics but I feel the question of whether `tests/codegen/{vec,array,slice}` should exist is more subtle than these choices, as it might be better to group such related tests by other topics like bounds check elision, thus I avoided making it.

Language
--------

- [Uplift `clippy::fn_null_check` lint as `useless_ptr_null_checks`.]
  (rust-lang/rust#111717)
- [Make `noop_method_call` warn by default.]
  (rust-lang/rust#111916)
- [Support interpolated block for `try` and `async` in macros.]
  (rust-lang/rust#112953)
- [Make `unconditional_recursion` lint detect recursive drops.]
  (rust-lang/rust#113902)
- [Future compatibility warning for some impls being incorrectly
  considered not overlapping.]
  (rust-lang/rust#114023)
- [The `invalid_reference_casting` lint is now **deny-by-default**
  (instead of allow-by-default)]
  (rust-lang/rust#112431)

Compiler
--------

- [Write version information in a `.comment` section like GCC/Clang.]
  (rust-lang/rust#97550)
- [Add documentation on v0 symbol mangling.]
  (rust-lang/rust#97571)
- [Stabilize `extern "thiscall"` and `"thiscall-unwind"` ABIs.]
  (rust-lang/rust#114562)
- [Only check outlives goals on impl compared to trait.]
  (rust-lang/rust#109356)
- [Infer type in irrefutable slice patterns with fixed length as array.]
  (rust-lang/rust#113199)
- [Discard default auto trait impls if explicit ones exist.]
  (rust-lang/rust#113312)
- Add several new tier 3 targets:
    - [`aarch64-unknown-teeos`]
      (rust-lang/rust#113480)
    - [`csky-unknown-linux-gnuabiv2`]
      (rust-lang/rust#113658)
    - [`riscv64-linux-android`]
      (rust-lang/rust#112858)
    - [`riscv64gc-unknown-hermit`]
      (rust-lang/rust#114004)
    - [`x86_64-unikraft-linux-musl`]
      (rust-lang/rust#113411)
    - [`x86_64-unknown-linux-ohos`]
      (rust-lang/rust#113061)
- [Add `wasm32-wasi-preview1-threads` as a tier 2 target.]
  (rust-lang/rust#112922)

Refer to Rust's [platform support page][platform-support-doc]
for more information on Rust's tiered platform support.

Libraries
---------

- [Add `Read`, `Write` and `Seek` impls for `Arc<File>`.]
  (rust-lang/rust#94748)
- [Merge functionality of `io::Sink` into `io::Empty`.]
  (rust-lang/rust#98154)
- [Implement `RefUnwindSafe` for `Backtrace`]
  (rust-lang/rust#100455)
- [Make `ExitStatus` implement `Default`]
  (rust-lang/rust#106425)
- [`impl SliceIndex<str> for (Bound<usize>, Bound<usize>)`]
  (rust-lang/rust#111081)
- [Change default panic handler message format.]
  (rust-lang/rust#112849)
- [Cleaner `assert_eq!` & `assert_ne!` panic messages.]
  (rust-lang/rust#111071)
- [Correct the (deprecated) Android `stat` struct definitions.]
  (rust-lang/rust#113130)

Stabilized APIs
---------------

- [Unsigned `{integer}::div_ceil`]
  (https://doc.rust-lang.org/stable/std/primitive.u32.html#method.div_ceil)
- [Unsigned `{integer}::next_multiple_of`]
  (https://doc.rust-lang.org/stable/std/primitive.u32.html#method.next_multiple_of)
- [Unsigned `{integer}::checked_next_multiple_of`]
  (https://doc.rust-lang.org/stable/std/primitive.u32.html#method.checked_next_multiple_of)
- [`std::ffi::FromBytesUntilNulError`]
  (https://doc.rust-lang.org/stable/std/ffi/struct.FromBytesUntilNulError.html)
- [`std::os::unix::fs::chown`]
  (https://doc.rust-lang.org/stable/std/os/unix/fs/fn.chown.html)
- [`std::os::unix::fs::fchown`]
  (https://doc.rust-lang.org/stable/std/os/unix/fs/fn.fchown.html)
- [`std::os::unix::fs::lfchown`]
  (https://doc.rust-lang.org/stable/std/os/unix/fs/fn.lchown.html)
- [`LocalKey::<Cell<T>>::get`]
  (https://doc.rust-lang.org/stable/std/thread/struct.LocalKey.html#method.get)
- [`LocalKey::<Cell<T>>::set`]
  (https://doc.rust-lang.org/stable/std/thread/struct.LocalKey.html#method.set)
- [`LocalKey::<Cell<T>>::take`]
  (https://doc.rust-lang.org/stable/std/thread/struct.LocalKey.html#method.take)
- [`LocalKey::<Cell<T>>::replace`]
  (https://doc.rust-lang.org/stable/std/thread/struct.LocalKey.html#method.replace)
- [`LocalKey::<RefCell<T>>::with_borrow`]
  (https://doc.rust-lang.org/stable/std/thread/struct.LocalKey.html#method.with_borrow)
- [`LocalKey::<RefCell<T>>::with_borrow_mut`]
  (https://doc.rust-lang.org/stable/std/thread/struct.LocalKey.html#method.with_borrow_mut)
- [`LocalKey::<RefCell<T>>::set`]
  (https://doc.rust-lang.org/stable/std/thread/struct.LocalKey.html#method.set-1)
- [`LocalKey::<RefCell<T>>::take`]
  (https://doc.rust-lang.org/stable/std/thread/struct.LocalKey.html#method.take-1)
- [`LocalKey::<RefCell<T>>::replace`]
  (https://doc.rust-lang.org/stable/std/thread/struct.LocalKey.html#method.replace-1)

These APIs are now stable in const contexts:

- [`rc::Weak::new`]
  (https://doc.rust-lang.org/stable/alloc/rc/struct.Weak.html#method.new)
- [`sync::Weak::new`]
  (https://doc.rust-lang.org/stable/alloc/sync/struct.Weak.html#method.new)
- [`NonNull::as_ref`]
  (https://doc.rust-lang.org/stable/core/ptr/struct.NonNull.html#method.as_ref)

Cargo
-----

- [Encode URL params correctly for `SourceId` in `Cargo.lock`.]
  (rust-lang/cargo#12280)
- [Bail out an error when using `cargo::` in custom build script.]
  (rust-lang/cargo#12332)

Compatibility Notes
-------------------

- [Update the minimum external LLVM to 15.]
  (rust-lang/rust#114148)
- [Check for non-defining uses of return position `impl Trait`.]
  (rust-lang/rust#112842)

Internal Changes
----------------

These changes do not affect any public interfaces of Rust, but they represent
significant improvements to the performance or internals of rustc and related
tools.

- [Remove LLVM pointee types, supporting only opaque pointers.]
  (rust-lang/rust#105545)
- [Port PGO/LTO/BOLT optimized build pipeline to Rust.]
  (rust-lang/rust#112235)
- [Replace in-tree `rustc_apfloat` with the new version of the crate.]
  (rust-lang/rust#113843)
- [Update to LLVM 17.]
  (rust-lang/rust#114048)
- [Add `internal_features` lint for internal unstable features.]
  (rust-lang/rust#108955)
- [Mention style for new syntax in tracking issue template.]
  (rust-lang/rust#113586)

cleanup: remove pointee types

This can't be merged until the oldest LLVM version we support uses opaque pointers, which will be the case after rust-lang#114148. (Also note `-Cllvm-args="-opaque-pointers=0"` can technically be used in LLVM 15, though I don't think we should support that configuration.)

I initially hoped this would provide some minor perf win, but in rust-lang#105412 (comment) it had very little impact, so this is only valuable as a cleanup.

As a followup, this will enable rust-lang#96242 to be resolved.

r? `@ghost`

`@rustbot` label S-blocked

ci: add a runner for vanilla LLVM 17

For CI cost, this can be seen as replacing the llvm-14 runner we dropped in rust-lang#114148.

Also, I've set `IS_NOT_LATEST_LLVM` in the llvm-16 runner, since that's not the latest anymore.

Pkgsrc changes:
 * Adjust patches and cargo checksums to new versions.
 * For an external LLVM, set dependency of llvm >= 15, in accordance
   with the upstream changes.
 * Add a patch with a backport from LLVM 17.0.3 fixing codegen for
   PPC, ref. rust-lang/rust#116845

Upstream changes:

Version 1.73.0 (2023-10-05)
==========================

Language
--------

- [Uplift `clippy::fn_null_check` lint as `useless_ptr_null_checks`.]
  (rust-lang/rust#111717)
- [Make `noop_method_call` warn by default.]
  (rust-lang/rust#111916)
- [Support interpolated block for `try` and `async` in macros.]
  (rust-lang/rust#112953)
- [Make `unconditional_recursion` lint detect recursive drops.]
  (rust-lang/rust#113902)
- [Future compatibility warning for some impls being incorrectly
  considered not overlapping.]
  (rust-lang/rust#114023)
- [The `invalid_reference_casting` lint is now **deny-by-default**
  (instead of allow-by-default)]
  (rust-lang/rust#112431

Compiler
--------

- [Write version information in a `.comment` section like GCC/Clang.]
  (rust-lang/rust#97550)
- [Add documentation on v0 symbol mangling.]
  (rust-lang/rust#97571)
- [Stabilize `extern "thiscall"` and `"thiscall-unwind"` ABIs.]
  (rust-lang/rust#114562)
- [Only check outlives goals on impl compared to trait.]
  (rust-lang/rust#109356)
- [Infer type in irrefutable slice patterns with fixed length as array.]
  (rust-lang/rust#113199)
- [Discard default auto trait impls if explicit ones exist.]
  (rust-lang/rust#113312)
- Add several new tier 3 targets:
    - [`aarch64-unknown-teeos`]
      (rust-lang/rust#113480)
    - [`csky-unknown-linux-gnuabiv2`]
      (rust-lang/rust#113658)
    - [`riscv64-linux-android`]
      (rust-lang/rust#112858)
    - [`riscv64gc-unknown-hermit`]
      (rust-lang/rust#114004)
    - [`x86_64-unikraft-linux-musl`]
      (rust-lang/rust#113411)
    - [`x86_64-unknown-linux-ohos`]
      (rust-lang/rust#113061)
- [Add `wasm32-wasi-preview1-threads` as a tier 2 target.]
  (rust-lang/rust#112922)

Refer to Rust's [platform support page][platform-support-doc]
for more information on Rust's tiered platform support.

Libraries
---------

- [Add `Read`, `Write` and `Seek` impls for `Arc<File>`.]
  (rust-lang/rust#94748)
- [Merge functionality of `io::Sink` into `io::Empty`.]
  (rust-lang/rust#98154)
- [Implement `RefUnwindSafe` for `Backtrace`]
  (rust-lang/rust#100455)
- [Make `ExitStatus` implement `Default`]
  (rust-lang/rust#106425)
- [`impl SliceIndex<str> for (Bound<usize>, Bound<usize>)`]
  (rust-lang/rust#111081)
- [Change default panic handler message format.]
  (rust-lang/rust#112849)
- [Cleaner `assert_eq!` & `assert_ne!` panic messages.]
  (rust-lang/rust#111071)
- [Correct the (deprecated) Android `stat` struct definitions.]
  (rust-lang/rust#113130)

Stabilized APIs
---------------

- [Unsigned `{integer}::div_ceil`]
  (https://doc.rust-lang.org/stable/std/primitiv e.u32.html#method.div_ceil)
- [Unsigned `{integer}::next_multiple_of`]
  (https://doc.rust-lang.org/stable/std/primitive.u32.html#method.next_multiple_of)
- [Unsigned `{integer}::checked_next_multiple_of`]
  (https://doc.rust-lang.org/stable/std/primitive.u32.html#method.checked_next_multiple_of)
- [`std::ffi::FromBytesUntilNulError`]
  (https://doc.rust-lang.org/stable/std/ffi/struct.FromBytesUntilNulError.html)
- [`std::os::unix::fs::chown`]
  (https://doc.rust-lang.org/stable/std/os/unix/fs/fn.chown.html)
- [`std::os::unix::fs::fchown`]
  (https://doc.rust-lang.org/stable/std/os/unix/fs/fn.fchown.html)
- [`std::os::unix::fs::lfchown`]
  (https://doc.rust-lang.org/stable/std/os/unix/fs/fn.lchown.html)
- [`LocalKey::<Cell<T>>::get`]
  (https://doc.rust-lang.org/stable/std/thread/struct.LocalKey.html#method.get)
- [`LocalKey::<Cell<T>>::set`]
  (https://doc.rust-lang.org/stable/std/thread/struct.LocalKey.html#method.set)
- [`LocalKey::<Cell<T>>::take`]
  (https://doc.rust-lang.org/stable/std/thread/struct.LocalKey.html#method.take)
- [`LocalKey::<Cell<T>>::replace`]
  (https://doc.rust-lang.org/stable/std/thread/struct.LocalKey.html#method.replace)
- [`LocalKey::<RefCell<T>>::with_borrow`]
  (https://doc.rust-lang.org/stable/std/thread/struct.LocalKey.html#method.with_borrow)
- [`LocalKey::<RefCell<T>>::with_borrow_mut`]
  (https://doc.rust-lang.org/stable/std/thread/struct.LocalKey.html#method.with_borrow_mut)
- [`LocalKey::<RefCell<T>>::set`]
  (https://doc.rust-lang.org/stable/std/thread/struct.LocalKey.html#method.set-1)
- [`LocalKey::<RefCell<T>>::take`]
  (https://doc.rust-lang.org/stable/std/thread/struct.LocalKey.html#method.take-1)
- [`LocalKey::<RefCell<T>>::replace`]
  (https://doc.rust-lang.org/stable/std/thread/struct.LocalKey.html#method.replace-1)

These APIs are now stable in const contexts:

- [`rc::Weak::new`]
  (https://doc.rust-lang.org/stable/alloc/rc/struct.Weak.html#method.new)
- [`sync::Weak::new`]
  (https://doc.rust-lang.org/stable/alloc/sync/struct.Weak.html#method.new)
- [`NonNull::as_ref`]
  (https://doc.rust-lang.org/stable/core/ptr/struct.NonNull.html#method.as_ref)

Cargo
-----

- [Encode URL params correctly for `SourceId` in `Cargo.lock`.]
  (rust-lang/cargo#12280)
- [Bail out an error when using `cargo::` in custom build script.]
  (rust-lang/cargo#12332)

Misc
----

Compatibility Notes
-------------------

- [Update the minimum external LLVM to 15.]
  (rust-lang/rust#114148)
- [Check for non-defining uses of return position `impl Trait`.]
  (rust-lang/rust#112842)

Internal Changes
----------------

These changes do not affect any public interfaces of Rust, but they
represent significant improvements to the performance or internals
of rustc and related tools.

- [Remove LLVM pointee types, supporting only opaque pointers.]
  (rust-lang/rust#105545)
- [Port PGO/LTO/BOLT optimized build pipeline to Rust.]
  (rust-lang/rust#112235)
- [Replace in-tree `rustc_apfloat` with the new version of the crate.]
  (rust-lang/rust#113843)
- [Update to LLVM 17.]
  (rust-lang/rust#114048)
- [Add `internal_features` lint for internal unstable features.]
  (rust-lang/rust#108955)
- [Mention style for new syntax in tracking issue template.]
  (rust-lang/rust#113586)

Update the minimum external LLVM to 16.

With this change, we'll have stable support for LLVM 16 and 17.
For reference, the previous increase to LLVM 15 was rust-lang#114148

[Relevant zulip discussion](https://rust-lang.zulipchat.com/#narrow/stream/131828-t-compiler/topic/riscv.20forced-atomics)

Remove handling for previously dropped LLVM version

LLVM 14 support was dropped in rust-lang#114148, so this LLVM version check is no longer required.

Rollup merge of rust-lang#122198 - beetrees:no-llvm-14, r=cuviper

Remove handling for previously dropped LLVM version

LLVM 14 support was dropped in rust-lang#114148, so this LLVM version check is no longer required.