[clang] [clang] fix RecursiveASTVisitor traversal from type to decl (PR #132551)

[Matheus Izvekov via cfe-commits]

mizvekov wrote:

Which host type twice?

In case the MemberPointerType represents a class adjustment, this visits the actual class type, instead of just the as-written qualifier.

example: https://gcc.godbolt.org/z/M5qfGPGMf

I didn't expect we would have in-tree users of the RecursiveVisitor for this, but it seems useful for external users to leave it in, no?

https://github.com/llvm/llvm-project/pull/132551