[llvm] [UTC] Don't leave dangling CHECK-SAME when removing CHECK lines (PR #82569)

[Alexander Richardson via llvm-commits]

https://github.com/arichardson approved this pull request.

LGTM assuming all tests are passing (do the other update scripts need changes too, e.g. update_cc_test_checks.py?)

https://github.com/llvm/llvm-project/pull/82569