[clang] [clang][NFC] Precommit test file refactoring (PR #125944)

[Paul Kirth via cfe-commits]

ilovepi wrote:

### Merge activity

* **Feb 5, 5:07 PM EST**: A user started a stack merge that includes this pull request via [Graphite](https://app.graphite.dev/github/pr/llvm/llvm-project/125944).


https://github.com/llvm/llvm-project/pull/125944