[clang] [CIR][NFC] Clean up constant op comments (PR #162142)

[Henrich Lauko via cfe-commits]

xlauko wrote:

### Merge activity

* **Oct 7, 8:12 AM UTC**: A user started a stack merge that includes this pull request via [Graphite](https://app.graphite.dev/github/pr/llvm/llvm-project/162142).


https://github.com/llvm/llvm-project/pull/162142