Fix failing torchscript test for xlnet

model.parameters() order is apparently not stable (only for xlnet, for some reason)

tests/test_modeling_common.py

@@ -236,11 +236,14 @@ class ModelTesterMixin:
             loaded_model.to(torch_device)
             loaded_model.eval()
 
-            model_params = model.parameters()
-            loaded_model_params = loaded_model.parameters()
+            model_state_dict = model.state_dict()
+            loaded_model_state_dict = loaded_model.state_dict()
+
+            self.assertEqual(set(model_state_dict.keys()), set(loaded_model_state_dict.keys()))
 
             models_equal = True
-            for p1, p2 in zip(model_params, loaded_model_params):
+            for layer_name, p1 in model_state_dict.items():
+                p2 = loaded_model_state_dict[layer_name]
                 if p1.data.ne(p2.data).sum() > 0:
                     models_equal = False