[clang] [llvm] Reland "[HLSL] Implement the reflect HLSL function" (PR #125599)

[Deric Cheung via llvm-commits]

Icohedron wrote:

To get the PR up and running, I am just marking hwasan as unsupported for now.
A proper fix will be implemented later. The Issue #124045 will remain open to track this.

https://github.com/llvm/llvm-project/pull/125599