[llvm] [MIRPrinter] Don't print line break when there is no instructions (NFC) (PR #80147)

[Jay Foad via llvm-commits]

jayfoad wrote:

> @jayfoad @arsenm Do you have any suggestions for this PR? I would like to revert it until the end of the backport of LLVM 18. Otherwise, this could make backport difficult for the next few months.

Is there a specific backport you're worried about? Personally I would not revert. For most targets it only affects a few tests, and even if a backport does cause conflicts it should be easy to fix them manually.

https://github.com/llvm/llvm-project/pull/80147