[clang] [llvm] [clang] Add test run of 'dump_ast_matchers.py' (PR #165472)

[Aiden Grossman via cfe-commits]

https://github.com/boomanaiden154 approved this pull request.

LGTM. Probably would be good to get approval from someone on the clang side as well.

https://github.com/llvm/llvm-project/pull/165472