[clang] [lldb] [clang] Add -ast-dump-filter-path to filter AST dump by file path (PR #194266)

[Aaron Ballman via cfe-commits]

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

Sorry for the delayed review, this LGTM aside from needing to fix a merge conflict and a few tiny cleanups, presuming precommit CI comes back green (it seems to be stuck currently).

https://github.com/llvm/llvm-project/pull/194266