[Clang] VectorExprEvaluator::VisitCallExpr / InterpretBuiltin - allow AVX/AVX512 subvector extraction intrinsics to be used in constexpr #157712 (#162836)

**This PR supersedes and replaces PR #158853**

The original branch diverged too far from the main branch, resulting in
significant merge conflicts that were difficult to resolve cleanly. To
provide a clean and reviewable history, this new PR was created by
cherry-picking the necessary commits onto a fresh branch based on the
latest `main`.

---

*(Original Description)*

This patch enables the use of AVX/AVX512 subvector extraction intrinsics
within `constexpr` functions. This is achieved by implementing the
evaluation logic for these intrinsics in
`VectorExprEvaluator::VisitCallExpr` and `InterpretBuiltin`.

The original discussion and review comments can be found in the previous
pull request for context: #158853

Fixes #157712
13 files changed
tree: 70d8d08972d21e47d98584e491f38f8e7f75308a
  1. .ci/
  2. .github/
  3. bolt/
  4. clang/
  5. clang-tools-extra/
  6. cmake/
  7. compiler-rt/
  8. cross-project-tests/
  9. flang/
  10. flang-rt/
  11. libc/
  12. libclc/
  13. libcxx/
  14. libcxxabi/
  15. libsycl/
  16. libunwind/
  17. lld/
  18. lldb/
  19. llvm/
  20. llvm-libgcc/
  21. mlir/
  22. offload/
  23. openmp/
  24. orc-rt/
  25. polly/
  26. runtimes/
  27. third-party/
  28. utils/
  29. .clang-format
  30. .clang-format-ignore
  31. .clang-tidy
  32. .git-blame-ignore-revs
  33. .gitattributes
  34. .gitignore
  35. .mailmap
  36. CODE_OF_CONDUCT.md
  37. CONTRIBUTING.md
  38. LICENSE.TXT
  39. pyproject.toml
  40. README.md
  41. SECURITY.md
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