[llvm] [AMDGPU] Add flag to force emit s_nop (PR #117839)

[Jay Foad via llvm-commits]

https://github.com/jayfoad commented:

Will this put nops inside bundles? See `mask_hazard_getpc2` in `test/CodeGen/AMDGPU/valu-mask-write-hazard.mir` for an example.

https://github.com/llvm/llvm-project/pull/117839