[clang-tools-extra] [clang-tidy] Add performance-redundant-lookup check (PR #125420)

[Oliver Stöneberg via cfe-commits]

firewave wrote:

I ran it on the Cppcheck codebase and there were several cases I would consider false positives as well as some which are really awkward to fix (in some cases leading to potentially unnecessary lookups). I will provide some examples in the next few days.

https://github.com/llvm/llvm-project/pull/125420