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

[Quentin Dian via llvm-commits]

DianQK 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.

This happens to affect my #79820 PR. 😅
Yes. It's easy, so let's look at it this way for a moment.


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