[clang] [Clang] Fix Microsoft ABI inheritance model when member pointer is used in a base specifier (PR #91990)

[Max Winkler via cfe-commits]

MaxEW707 wrote:

@Endilll Wondering if this PR gets the green check from you.

I would like to get this merged before the clang-19 branch is created and just want to get the green light from a more senior member of the community before merging. Thanks :).

https://github.com/llvm/llvm-project/pull/91990