[hal/metal] Mesh Shaders

[inner-daemons]

Connections
Related #7197
Similar to #8110

Description
Adds mesh shaders to metal backend

Testing
None yet

Squash or Rebase?

Squash

Checklist

• Run cargo fmt.
• Run taplo format.
• Run cargo clippy --tests. If applicable, add:
  • --target wasm32-unknown-unknown
• Run cargo xtask test to run tests.
• If this contains user-facing changes, add a CHANGELOG.md entry.

[cwfitzgerald]

Just to manage expectations, assuming I can get your current comments addressed, should I expect this to be merged soon?

Yeah no big problems I can see, all the tests pass and the CTS passes, so outside of concerns with the code, I'm happy to land.

[inner-daemons]

Unfortunately it seems the CI doesn't support mesh shaders, since I think it only supports Metal2. So we won't get that advantage.

Related, I believe I've uncovered a logical error in feature detection for int64 and scoped simd, will report

[cwfitzgerald]

Laaame, alright

[inner-daemons]

@cwfitzgerald I didn't probably address all your comments correctly but can you take a look at what I said

[cwfitzgerald]

Much better, some more cleanup comments, then we should be good.

[cwfitzgerald]

Tests pass, cts passes, lets do this.