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

[Nikita Popov via cfe-commits]

nikic wrote:

It looks like this breaks the clang stage 2 build: https://llvm-compile-time-tracker.com/show_error.php?commit=3cdb30ebbc18fa894d3bd67aebcff76ce7c741ac

https://github.com/llvm/llvm-project/pull/104458