[All models] Extend config.output_attentions with output_attentions function arguments (#4538)

* DOC: Replace instances of ``config.output_attentions`` with function argument ``output_attentions``

* DOC: Apply Black Formatting

* Fix errors where output_attentions was undefined

* Remove output_attentions in classes per review

* Fix regressions on tests having `output_attention`

* Fix further regressions in tests relating to `output_attentions`

Ensure proper propagation of `output_attentions` as a function parameter
to all model subclasses

* Fix more regressions in `test_output_attentions`

* Fix issues with BertEncoder

* Rename related variables to `output_attentions`

* fix pytorch tests

* fix bert and gpt2 tf

* Fix most TF tests for `test_output_attentions`

* Fix linter errors and more TF tests

* fix conflicts

* DOC: Apply Black Formatting

* Fix errors where output_attentions was undefined

* Remove output_attentions in classes per review

* Fix regressions on tests having `output_attention`

* fix conflicts

* fix conflicts

* fix conflicts

* fix conflicts

* fix pytorch tests

* fix conflicts

* fix conflicts

* Fix linter errors and more TF tests

* fix tf tests

* make style

* fix isort

* improve output_attentions

* improve tensorflow

Co-authored-by: Patrick von Platen <patrick.v.platen@gmail.com>

tests/test_modeling_xlnet.py

@@ -238,7 +238,7 @@ class XLNetModelTest(ModelTesterMixin, unittest.TestCase):
             model.to(torch_device)
             model.eval()
 
-            _, _, attentions = model(input_ids_1, target_mapping=target_mapping)
+            _, _, attentions = model(input_ids_1, target_mapping=target_mapping, output_attentions=True)
 
             self.parent.assertEqual(len(attentions), config.n_layer)
             self.parent.assertIsInstance(attentions[0], tuple)
@@ -483,7 +483,6 @@ class XLNetModelTest(ModelTesterMixin, unittest.TestCase):
     def test_xlnet_base_model_with_att_output(self):
         self.model_tester.set_seed()
         config_and_inputs = self.model_tester.prepare_config_and_inputs()
-        config_and_inputs[0].output_attentions = True
         self.model_tester.create_and_check_xlnet_base_model_with_att_output(*config_and_inputs)
 
     def test_xlnet_lm_head(self):