Revert "[Offload][OpenMP] remove SourceInfo::removePath (#226283)" (#226557)

This reverts commit 5b8e65685b4fe99191a217bfa0527c51cf36925c.

In https://github.com/llvm/llvm-project/pull/226283 I forgot to update
info.c to account for the full file paths in its output, will update
commit with fixed test and re open PR

GitOrigin-RevId: 68d354f5795682ea1fe03304ac3e7b2a43a36b0d