[clang] [llvm] [DirectX] Add target builtins (PR #134439)

[Deric C. via llvm-commits]

https://github.com/Icohedron approved this pull request.

I like this change. It helps makes implementing builtins more consistent between SPIR-V and DirectX/DXIL

https://github.com/llvm/llvm-project/pull/134439