[llvm] [RemoveDIs][DebugInfo] Verifier and printing fixes for DPLabel (PR #83242)

[Stephen Tozer via llvm-commits]

SLTozer wrote:

I can't say with certainty from just that information, but this error could appear if there is an ODR violation. While you work on the reduced reproducer (which can be time consuming with LTO builds in my experience), can you verify whether, for the type of the variable that this error appears for, there are multiple non-identical class definitions with that type's name?

https://github.com/llvm/llvm-project/pull/83242