Clean up friend template warnings from tests.

../../../tests/Common/Common.h:798:12: warning: class ‘FriendTemplate<T>’ is implicitly friends with itself [enabled by default]
     friend FriendTemplate;
            ^
../../../tests/Common/Common.h:799:18: warning: class ‘FriendTemplate<T>’ is implicitly friends with itself [enabled by default]
     friend class FriendTemplate;

tests/Common/Common.h

@@ -795,9 +795,6 @@ template<typename T> class FriendTemplate
     template<typename TT>
     friend FriendTemplate<TT> func(const FriendTemplate<TT>&);
 
-    friend FriendTemplate;
-    friend class FriendTemplate;
-
     template<typename TT>
     friend class FriendTemplate;
 };