[clang] [llvm] [HLSL] Add HLSL unpack intrinsics (PR #228518)

[via llvm-commits]

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

The change looks correct to me. I've left some comments to improve tests.

This patch fixes issues: https://github.com/llvm/llvm-project/issues/99223, https://github.com/llvm/llvm-project/issues/99226, https://github.com/llvm/llvm-project/issues/99224 and https://github.com/llvm/llvm-project/issues/99222 should be included in the patch summary.

https://github.com/llvm/llvm-project/pull/228518