Big TF test cleanup (#24282)

* Fix one BLIP arg not being optional, remove misspelled arg

* Remove the lxmert test overrides and just use the base test_saved_model_creation

* saved_model_creation fixes and re-enabling tests across the board

* Remove unnecessary skip

* Stop caching sinusoidal embeddings in speech_to_text

* Fix transfo_xl compilation

* Fix transfo_xl compilation

* Fix the conditionals in xglm

* Set the save spec only when building

* Clarify comment

* Move comment correctly

* Correct embeddings generation for speech2text

* Mark RAG generation tests as @slow

* Remove redundant else:

* Add comment to clarify the save_spec line in build()

* Fix size tests for XGLM at last!

* make fixup

* Remove one band_part operation

* Mark test_keras_fit as @slow

tests/models/data2vec/test_modeling_tf_data2vec_vision.py

@@ -347,6 +347,7 @@ class TFData2VecVisionModelTest(TFModelTesterMixin, PipelineTesterMixin, unittes
             check_hidden_states_output(inputs_dict, config, model_class)
 
     # Overriding this method since the base method won't be compatible with Data2VecVision.
+    @slow
     def test_keras_fit(self):
         config, _ = self.model_tester.prepare_config_and_inputs_for_common()
         for model_class in self.all_model_classes: