GVariantType test case: assert all memory freed

Make sure we've freed all TypeInfos at the end of the test.

glib/tests/gvarianttype.c

@@ -1025,6 +1025,8 @@ test_gvarianttypeinfo (void)
       g_variant_type_free (type);
       g_free (desc);
     }
+
+  assert_no_type_infos ();
 }
 
 int