[clang] [Clang] Fix -Wunused-private-field false negative with defaulted comparison operators (PR #116871)

[Chris White via cfe-commits]

whiteio wrote:

I'll update my changes to fix the other tests that are failing this evening, sorry about that, should have ran the rest of them after making the change.

https://github.com/llvm/llvm-project/pull/116871