[clang] Reland: [clang] Finish implementation of P0522 (PR #111711)

[Mikhail Goncharov via cfe-commits]

metaflow wrote:

oh, that might become messy quickly. Do you know if 4dadf42c1a74dd4e37db9ffd6fbb3027f59751a7 and 224519b08945637a85e9798c78286643288f7b77 depend on this PR and should also be reverted?

https://github.com/llvm/llvm-project/pull/111711