[clang] [llvm] [HLSL] Implement dot2add intrinsic (PR #131237)

[Farzon Lotfi via llvm-commits]

farzonl wrote:

This looks mostly fine, but the Prototype changes also mean we likely need to change up what you are doing in Sema.

 As an aside you need to rebase to resolve a merge conflict. 

https://github.com/llvm/llvm-project/pull/131237