[clang] [AArch64][Clang] Refactor code to emit SVE & SME builtins (PR #70959)

[Sander de Smalen via cfe-commits]

https://github.com/sdesmalen-arm approved this pull request.

This patch was reviewed as part of PR #70662, so I'm happy for this patch to reland.

https://github.com/llvm/llvm-project/pull/70959