[clang] [Clang] Fix name lookup for dependent bases (PR #114978)

[Nikita Popov via cfe-commits]

nikic wrote:

FYI this seems to have significant cost for some types of C++ code, in particular clang build time regresses by 0.35% (https://llvm-compile-time-tracker.com/compare.php?from=4a7b56e6e7dd0f83c379ad06b6e81450bc691ba6&to=486644723038555a224fd09d462bb5099e64809e&stat=instructions:u).

https://github.com/llvm/llvm-project/pull/114978