[clang] Reapply "[Clang][Sema] Use the correct lookup context when building overloaded 'operator->' in the current instantiation (#104458)" (PR #109422)

[Cassie Jones via cfe-commits]

porglezomp wrote:

I'm testing this and seeing some further behavior changes on dependent typenames with `->`.
I'm currently trying to reduce and determine if the behavior is correct or not.

https://github.com/llvm/llvm-project/pull/109422