[llvm] Introduce and use Verifier::visitDIType (PR #189067)

[Tom Tromey via llvm-commits]

tromey wrote:

Missed one test that fails the new check --  I'll fix this momentarily.

While looking at this I see that `DIModule` also takes a line number (but stores it differently).  So perhaps the new verifier check should be extended to cover this class as well.

https://github.com/llvm/llvm-project/pull/189067