[llvm] [DI] Have createClassType create a class type. (PR #102624)

[via llvm-commits]

deadalnix wrote:

The code I'm updating here is used through the C API. I'm not sure what API clang uses, I'm not familiar with the clang codebase, but not this one, because it generates proper DW_TAG_class_type debug infos.

https://github.com/llvm/llvm-project/pull/102624