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

[Aaron Ballman via cfe-commits]

AaronBallman wrote:

> Can you update the description too? No changelog needed, I assume we want to backport that @AaronBallman

If we can backport it, it seems like a reasonable one to backport; the biggest question I have is whether we have any concerns about the changes being risky or not.

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