[llvm] [NFC][LLVM-Tests] Specialize test suite for LLVM unit tests (PR #161442)

[Rahul Joshi via llvm-commits]

jurahul wrote:

But for additional verification I created this PR with a broken unit test, expecting that it will fail the checks: https://github.com/llvm/llvm-project/pull/161623

https://github.com/llvm/llvm-project/pull/161442