Improving pipeline tests (#12784)

* Proposal

* Testing pipelines slightly better.

- Overall same design
- Metaclass to get proper different tests instead of subTest (not well
supported by Pytest)
- Added ANY meta object to make output checking more readable.
- Skipping architectures either without tiny_config or without
architecture.

* Small fix.

* Fixing the tests in case of None value.

* Oups.

* Rebased with more architectures.

* Fixing reformer tests (no override anymore).

* Adding more options for model tester config.

Co-authored-by: Lysandre <lysandre.debut@reseau.eseo.fr>

tests/test_modeling_reformer.py

@@ -186,6 +186,11 @@ class ReformerModelTester:
             hash_seed=self.hash_seed,
         )
 
+    def get_pipeline_config(self):
+        config = self.get_config()
+        config.vocab_size = 100
+        return config
+
     def create_and_check_reformer_model(self, config, input_ids, input_mask, choice_labels):
         model = ReformerModel(config=config)
         model.to(torch_device)