[llvm] [BranchFolding] Merge debug locs on common hoisted code (PR #140063)

[Jeremy Morse via llvm-commits]

https://github.com/jmorse approved this pull request.

This LGTM but I think we should leave it a little time for others to chip in. I feel like asserting that TI and FI are identical would help, but that Should (TM) be guaranteed by the earlier loop in `HoistCommonCodeInSuccs`.

https://github.com/llvm/llvm-project/pull/140063