[llvm] [SPIR-V] Add pre-commit CI workflow (PR #74092)

[Tom Stellard via llvm-commits]

https://github.com/tstellar commented:

We depend a lot on ccache to get faster builds, do you know if adding `DLLVM_EXPERIMENTAL_TARGETS_TO_BUILD=spirv` makes any changes to header files that may invalidate the ccache data?

Would it make sense to start by having this job manually triggered either by a comment or a label?

How important is it to run this job on Windows and Mac OS?  We are resource constrained on those OSes.


https://github.com/llvm/llvm-project/pull/74092