[clang] [CMake][Release] Refactor cache file and use two stages for non-PGO builds (PR #89812)

[Tobias Hieta via cfe-commits]

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

I find changes to the multi-stage build caches a bit confusing to review without being able to see the cache that's generated. But I trust that you have tested this and it works as expected, In that case you can merge this.

https://github.com/llvm/llvm-project/pull/89812