[llvm] [nfc][ctx_prof] Efficient profile traversal and update (PR #110052)

[Mircea Trofin via llvm-commits]

mtrofin wrote:

### Merge activity

* **Sep 27, 11:08 AM EDT**: @mtrofin started a stack merge that includes this pull request via [Graphite](https://app.graphite.dev/github/pr/llvm/llvm-project/110052).


https://github.com/llvm/llvm-project/pull/110052