[llvm] [X86] Refuse machine outlining under Windows CFI (PR #225263)

[Demetrios Chiuratto Agourakis via llvm-commits]

agourakis82 wrote:

This is intentionally the conservative AArch64-equivalent fence, not a full WinEH-metadata-preserving outliner. Happy to iterate if reviewers want additional guards on top.

https://github.com/llvm/llvm-project/pull/225263