[llvm] [HLSL][DirectX] Lower llvm.dx.load.input and llvm.dx.store.output to DXIL (PR #208871)

[Dan Brown via llvm-commits]

danbrown-amd wrote:

My last commit restores the extra argument of llvm.dx.store.output because the change broke 11 existing tests.  I can change the tests instead if that's preferred.

https://github.com/llvm/llvm-project/pull/208871