[IROutliner] Make sure that loop debug info is stripped.

As pointed out in https://github.com/llvm/llvm-project/issues/54155#issuecomment-1057465479, there was a crash when loop info was being outlined. It was not being properly stripped and adjusted, so would point to the wrong location. This uses similar logic found in the CodeExtractor to adjust the loop debug info.

Reviewer: fhahn, paquette

Differential Revision: https://reviews.llvm.org/D120869