[clang][ptrauth] Sema queries for values containing address discrimination fail to consider vtable pointers

[ojhunt]

While investigating some changes to ptrauth tests from @cor3ntin's trivial relocation work I found that when determining whether a type contains address discriminated pointer auth we fail to consider vtable pointers.

This is not a fantastic thing.

[llvmbot]

@llvm/issue-subscribers-clang-frontend

Author: Oliver Hunt (ojhunt)

While investigating some changes to ptrauth tests from @cor3ntin's trivial relocation work I found that when determining whether a type contains address discriminated pointer auth we fail to consider vtable pointers.

This is not a fantastic thing.