test: unbreak on non-GTEST_HAS_DEATH_TEST platforms

test/test_device_changed_callback.cpp:79:3: error: use of undeclared identifier 'ASSERT_DEATH'
  ASSERT_DEATH(
  ^

test/test_device_changed_callback.cpp

@@ -76,7 +76,7 @@ void test_registering_second_callbacks(cubeb_stream * stream)
 
   // Get an assertion fails when registering a callback
   // without unregistering the original one.
-  ASSERT_DEATH(
+  ASSERT_DEATH_IF_SUPPORTED(
     cubeb_stream_register_device_changed_callback(stream, device_changed_callback),
     ""
   );