[clang-tools-extra] [clang-tidy][NFC] optimize cache for config option (PR #121406)

[Congcong Cai via cfe-commits]

HerrCai0907 wrote:

### Merge activity

* **Jan 10, 10:12 AM EST**: A user started a stack merge that includes this pull request via [Graphite](https://app.graphite.dev/github/pr/llvm/llvm-project/121406).


https://github.com/llvm/llvm-project/pull/121406