While debugging https://github.com/llvm/llvm-project/issues/71326, the `LoadOp::verify` code and error were very confusing. This PR improves that. This code was a part from the reverted PR https://github.com/llvm/llvm-project/pull/75519. Fixing the `-convert-vector-to-scf` issue is going to take a bit longer and this code was out of scope anyway. Co-authored-by: Benjamin Maxwell <macdue@dueutil.tech>