[multiple models] skip saving/loading deterministic state_dict keys (#7878)

* make the save_load special key tests common

* handle mbart

* cleaner solution

* fix

* move test_save_load_missing_keys back into fstm for now

* restore

* style

* add marian

* add pegasus

* blenderbot

* revert - no static embed

tests/test_modeling_marian.py

@@ -21,6 +21,8 @@ from transformers.file_utils import cached_property
 from transformers.hf_api import HfApi
 from transformers.testing_utils import require_sentencepiece, require_tokenizers, require_torch, slow, torch_device
 
+from .test_modeling_common import ModelTesterMixin
+
 
 if is_torch_available():
     import torch
@@ -35,6 +37,37 @@ if is_torch_available():
     from transformers.pipelines import TranslationPipeline
 
 
+@require_torch
+class ModelTester:
+    def __init__(self, parent):
+        self.config = MarianConfig(
+            vocab_size=99,
+            d_model=24,
+            encoder_layers=2,
+            decoder_layers=2,
+            encoder_attention_heads=2,
+            decoder_attention_heads=2,
+            encoder_ffn_dim=32,
+            decoder_ffn_dim=32,
+            max_position_embeddings=48,
+            add_final_layer_norm=True,
+            return_dict=True,
+        )
+
+    def prepare_config_and_inputs_for_common(self):
+        return self.config, {}
+
+
+@require_torch
+class SelectiveCommonTest(unittest.TestCase):
+    all_model_classes = (MarianMTModel,) if is_torch_available() else ()
+
+    test_save_load_keys_to_never_save = ModelTesterMixin.test_save_load_keys_to_never_save
+
+    def setUp(self):
+        self.model_tester = ModelTester(self)
+
+
 class ModelManagementTests(unittest.TestCase):
     @slow
     def test_model_names(self):