[llvm] [Debuginfo][GVNHoist] Fix #86227: update the debug location of the hoisted GEP (PR #86236)

[Stephen Tozer via llvm-commits]

https://github.com/SLTozer commented:

Change and test LGTM, with some minor nits for the test, and also `clang-format` is needed (you can see the suggested changes from the PR checks [here](https://github.com/llvm/llvm-project/actions/runs/8384940424/job/22963060233?pr=86236)).

https://github.com/llvm/llvm-project/pull/86236