[clang] [Clang]fix dependent qualified base member lookup crash (PR #199403)

[via cfe-commits]

Serosh-commits wrote:

> > I am confused, the patch still has the problem last discussed.
> 
> @Serosh-commits do you need clarification?

yeah would be grateful just a bit of direction and clarification https://github.com/llvm/llvm-project/pull/199403#discussion_r3303909592


https://github.com/llvm/llvm-project/pull/199403