Fix test_configuration_tie in FlaxEncoderDecoderModelTest (#14076)

* check test_configuration_tie

* Fix test_configuration_tie

* make test slow again

* Remove property and use model.module.bind

* revert to slow test

Co-authored-by: ydshieh <ydshieh@users.noreply.github.com>

Author: ydshieh

tests/test_modeling_flax_encoder_decoder.py

@@ -357,8 +357,11 @@ def get_decoder_config(self):
         return config
 
     def _check_configuration_tie(self, model):
-        assert id(model.decoder.config) == id(model.config.decoder)
-        assert id(model.encoder.config) == id(model.config.encoder)
+
+        module = model.module.bind(model.params)
+
+        assert id(module.decoder.config) == id(model.config.decoder)
+        assert id(module.encoder.config) == id(model.config.encoder)
 
     @slow
     def test_configuration_tie(self):