[clang-tools-extra] [clang-tidy][NFC] Add checks to tests that have no checks specified. (PR #170895)

[via cfe-commits]

google-yfyang wrote:

> I'm surprised it didn't break precommit CI, do you have any buildbots that flag this? Or it fails locally for you?

I am not familiar with the precommit CI to know why this isn't triggered. Perhaps these tests are disabled somehow? They fail downstream here in checks at Google. 

https://github.com/llvm/llvm-project/pull/170895