[llvm] [MIRPrinter] Don't print space when there is no successor (PR #80143)

[Quentin Dian via llvm-commits]

DianQK wrote:

> > This also prints two line breaks, and I think we can delete one.
> 
> But you haven't done that in this patch, right?

This breaks many test cases. If appropriate, I'll create another PR.

https://github.com/llvm/llvm-project/pull/80143