[llvm] [PGO] Preserve analysis results when nothing was instrumented (PR #93421)

[Pavel Samolysov via llvm-commits]

samolisov wrote:

The PR has been modified to contain NFC changes only to optimize the compilation time. All the changes related to `__llvm_profile_raw_version` will be submitted as a separated PR.

https://github.com/llvm/llvm-project/pull/93421