[clang] [compiler-rt] [clang-tools-extra] [PGO] Exposing PGO's Counter Reset and File Dumping APIs (PR #76471)

[Mingming Liu via cfe-commits]

https://github.com/minglotus-6 approved this pull request.

thanks! Mostly lg with a pending discussion on whether we want to have test coverage for `clang_pgogen` in `compiler-rt/test/profile/instrprof-api.c`, and the open-ended discussion about the observed build failure in another compiler-rt test.

https://github.com/llvm/llvm-project/pull/76471