[Headers][X86] Enable constexpr handling for MMX/SSE/AVX/AVX512 PMADDWD/PMADDUBSW intrinsics

[markbhasawut]

This PR updates the PMADDWD/PMADDUBSW builtins to support constant expression handling, by extending the VectorExprEvaluator::VisitCallExpr that handles interp__builtin_ia32_pmadd builtins.

Closes #155392

[github-actions]

✅ With the latest revision this PR passed the C/C++ code formatter.

[RKSimon]

Missing test coverage in sse2-builtins.c etc.

[markbhasawut]

Missing test coverage in sse2-builtins.c etc.

I'm working on it. Sorry for taking such a long time on the issue. 😅

[RKSimon]

Thanks @markbhasawut - mark this as "Ready for review" when you're done

[markbhasawut]

@RKSimon I tried to get this PR a label, but the automate-prs-labels didn't run even I triggered it by updating the branch. Do you have any suggestions?

[RKSimon]

Best way is just to use the Update button like I just did - it'll trigger fresh CI builds

[RKSimon]

LGTM - cheers!

[markbhasawut]

@RKSimon Thanks for your advice and reviewing!

[llvm-ci]

LLVM Buildbot has detected a new failure on builder clangd-ubuntu-tsan running on clangd-ubuntu-clang while building clang at step 2 "checkout".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/134/builds/27706

Here is the relevant piece of the build log for the reference

Step 2 (checkout) failure: update (failure)
git version 2.17.1
fatal: unable to access 'https://github.com/llvm/llvm-project.git/': Could not resolve host: github.com
fatal: unable to access 'https://github.com/llvm/llvm-project.git/': Could not resolve host: github.com