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

[Qiongsi Wu via llvm-commits]

qiongsiwu wrote:

Note to reviewers: I am only adding these three PGO functions because I am not sure if more should be added. Please let me know, and I will revise the PR. 

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