[llvm] LoopInfo: introduce Loop::getLocStr; unify debug output (PR #93051)

[Florian Hahn via llvm-commits]

fhahn wrote:

> > Can you add a test showing how the new debug info location is printed for new users?
> 
> This is done in #93208.

But that's separate from this patch, right? Still would be good to have a test here to check the behavior of the patch, could also be in LAA

https://github.com/llvm/llvm-project/pull/93051