[clang] [alpha.webkit.UncountedCallArgsChecker] Ignore methods of WTF String classes. (PR #90704)

[Ryosuke Niwa via cfe-commits]

rniwa wrote:

> LGTM! The revert was caused entirely by something in the mock headers in tests right?

Yeah, there were some typos in mock-types. Not sure why checks didn't catch it.

https://github.com/llvm/llvm-project/pull/90704