[libcxx] [test] Fix unary_function inheritance assumption.

[STL_MSFT]

Summary

Fix unary_function inheritance assumption.

C++11 didn't require std::hash to derive from std::unary_function. The portable thing to do is to inspect the typedefs, as the other half of this test was already doing.

[EricWF]

r274205.

test/std/containers/sequences/vector.bool/vector_bool.pass.cpp

int main()
     T vb(std::begin(ba), std::end(ba));
     H h;
     assert(h(vb) != 0);
     }
 #if TEST_STD_VER >= 11
     {
     typedef std::vector<bool, min_allocator<bool>> T;
     typedef std::hash<T> H;
-    static_assert((std::is_base_of<std::unary_function<T, std::size_t>,
-                                   H>::value), "");
+    static_assert((std::is_same<H::argument_type, T>::value), "" );
+    static_assert((std::is_same<H::result_type, std::size_t>::value), "" );
     bool ba[] = {true, false, true, true, false};
     T vb(std::begin(ba), std::end(ba));
     H h;
     assert(h(vb) != 0);
     }
 #endif
 }