[clang] Revert "[Clang][CMake] Use IRPGO instead of FE PGO for Cmake Caches (#155957)" (PR #159367)

[Aiden Grossman via cfe-commits]

https://github.com/boomanaiden154 approved this pull request.

The motivation for the revert needs to go in the PR description (which will become the commit description), not a comment.

I'll try and reproduce this locally on a AArch64 machine. If I can't, I'm going to need you to reproduce and send over a profile and maybe some bitcode. I'll reach out if I end up needing anything.

https://github.com/llvm/llvm-project/pull/159367