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

[Alexander Kornienko via cfe-commits]

alexfh wrote:

> @alexfh thanks, this will be fixed here: #132977

We see more clang crashes after #132977 / 960615954e4cb3150ae4a479fa7f9d0d17035eea. I'll start a reduction and will post a new test case, but please revert #132977 and this commit.

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