[clang] [Clang][X86] Introduce Clang ABI Gate for MSVC alignment (PR #210305)

[Mariya Podchishchaeva via cfe-commits]

Fznamznon wrote:

> Didn't we do that for vector deleting destructors because we had people who needed both ABIs? CC @Fznamznon

I think VDDs are guarded by -fclang-abi-compat because they break ABI compatibility.

https://github.com/llvm/llvm-project/pull/210305