[llvm] [MemProf][PGO] Prevent dropping of profile metadata during optimization (PR #121359)

[Teresa Johnson via llvm-commits]

teresajohnson wrote:

@DianQK adding you as it looks like you had added the calls to combineMetadata from MemCpyOpt. You might want to look at what other types of metadata should be preserved during these optimizations. Anything not given in the known ids list will be dropped.

https://github.com/llvm/llvm-project/pull/121359