[clang] [clang][HLSL] Add sign intrinsic part 4 (PR #108396)

[Farzon Lotfi via cfe-commits]

farzonl wrote:

@tgymnich I think its time for you to ask for commit access. Follow these steps: https://llvm.org/docs/DeveloperPolicy.html#obtaining-commit-access

https://github.com/llvm/llvm-project/pull/108396