[mlir][LLVM] Verify too many indices in GEP verifier (#70174)

The current verifier stopped verification with a success value as soon
as a type was encountered that cannot be indexed into. The correct
behaviour in this case is to error out as there are too many indices for
the element type. Not doing so leads to bad user-experience as an
invalid GEP is likely to fail only later during LLVM IR translation.

This PR implements the correct verification behaviour. Some tests
upstream had to also be fixed as they were creating invalid GEPs.

Fixes https://github.com/llvm/llvm-project/issues/70168