[clang] [Clang] Fix crash when type-name is combined with class specifier in template argument (PR #191689)

[Oliver Hunt via cfe-commits]

https://github.com/ojhunt requested changes to this pull request.

Need to think a bit about the corrective action right now, but at least the test case needs to be changed.

https://github.com/llvm/llvm-project/pull/191689