filter-streams: Cleanup custom classes in test

https://bugzilla.gnome.org/show_bug.cgi?id=711799

gio/tests/filter-streams.c

@@ -10,6 +10,7 @@
  *
  * Author: Ryan Lortie <desrt@desrt.ca>
  */
+#define G_CLEANUP_MODULE test
 
 #include <string.h>
 #include <glib/glib.h>
@@ -377,6 +378,8 @@ test_output_async (void)
   g_main_loop_unref (loop);
 }
 
+G_CLEANUP_DEFINE
+
 int
 main (int argc, char **argv)
 {