Remove the call to DiagnoseUseOfDecl in LookupMemberExpr because:
- LookupMemberExpr eagerly lookup both getter and setter, reguardless
if they are used or not. It causes wrong diagnostics if you are only
- LookupMemberExpr only diagnoses getter, but not setter.
- ObjCPropertyOpBuilder already DiagnoseUseOfDecl when building getter
and setter. Doing it again in LookupMemberExpr causes duplicated