[clang] [clang] Move DefaultedFunctionKind from Sema to AST (PR #214846)

[Michael Buch via cfe-commits]

https://github.com/Michael137 approved this pull request.

LGTM, given this will make enable re-use this in CGDebugInfo

Wait a few days before merging in case @AaronBallman @Sirraide @cor3ntin have concerns

https://github.com/llvm/llvm-project/pull/214846