[llvm] Verifier: More helpful error message for cross-function references (PR #82906)

[Nicolai Hähnle via llvm-commits]

nhaehnle wrote:

The Windows failure seems pretty unrelated (a Flang fir test, so AFAIUI not even involving LLVM IR?). Given the general instability of Windows tests (as discussed extensively on Discourse), I'm inclined to not take it seriously.

https://github.com/llvm/llvm-project/pull/82906