[clang] [CIR] Add lowering for the cir.vtable.address_point operation (PR #153243)

[Bruno Cardoso Lopes via cfe-commits]

https://github.com/bcardosolopes approved this pull request.

LGTM, minor suggestion that can be addressed (or not) as follow up.

https://github.com/llvm/llvm-project/pull/153243