[llvm] improve update_cc_test_checks.py for template (PR #102505)

[Alexander Richardson via llvm-commits]

arichardson wrote:

Do you have a test case for this? If so it would be good to add it to the existing set of tests (e.g. a test function that did not have test checks before)

https://github.com/llvm/llvm-project/pull/102505