[clang] [clang-tools-extra] Reland: [clang] NFC: Clear some uses of MemberPointerType::getClass (PR #132317)

[Alexander Kornienko via cfe-commits]

alexfh wrote:

Thanks for the fast fix! I would still insist on reverting first and recommiting the changes along with the fix (I could run this through a bit more testing on real code for more confidence), rather than trying to expedite  the review and potentially introducing more regressions.

https://github.com/llvm/llvm-project/pull/132317