[llvm] [FileCheck] Handle CHECK-EMPTY at EOF without trailing newline (PR #196576)

[Joel E. Denny via llvm-commits]

jdenny-ornl wrote:

Please generalize the PR title and initial comment beyond CHECK-EMPTY, which is simply the most likely case to suffer because it does not require a pattern.

https://github.com/llvm/llvm-project/pull/196576