[llvm] [RemoveDIs] Add DPLabels support [3a/3] (PR #82633)

[Orlando Cazalet-Hyams via llvm-commits]

OCHyams wrote:

Thanks @SLTozer

> For posterity, this patch stimulates the following tests...

Note that the tests are not actually stimulated until #82639 lands.

https://github.com/llvm/llvm-project/pull/82633