[compiler-rt] [llvm] [ctxprof] Capture sampling info for context roots (PR #131201)

[Mircea Trofin via llvm-commits]

mtrofin wrote:

### Merge activity

* **Mar 15, 12:08 AM EDT**: A user started a stack merge that includes this pull request via [Graphite](https://app.graphite.dev/github/pr/llvm/llvm-project/131201).


https://github.com/llvm/llvm-project/pull/131201