[llvm] Added feature in llvm-profdata merge to filter functions from the profile (PR #78378)

[Lei Wang via llvm-commits]

wlei-llvm wrote:

Thanks for the change. 
IIUC, it only supports filtering top-level functions, wondering if it's also useful for excluding the inlined(nested children) functions? thinking of some "investigating compilation bug" scenario, it might be necessary to ensure all the function copies are not loaded with a profile.

https://github.com/llvm/llvm-project/pull/78378