Better filtering of the model outputs in Trainer (#8633)

* Better filtering of the model outputs in Trainer

* Fix examples tests

* Add test for Lysandre

examples/seq2seq/seq2seq_trainer.py

@@ -1,4 +1,4 @@
-from typing import Any, Dict, Optional, Tuple, Union
+from typing import Any, Dict, List, Optional, Tuple, Union
 
 import torch
 from torch import nn
@@ -153,7 +153,11 @@ class Seq2SeqTrainer(Trainer):
         return loss
 
     def prediction_step(
-        self, model: nn.Module, inputs: Dict[str, Union[torch.Tensor, Any]], prediction_loss_only: bool
+        self,
+        model: nn.Module,
+        inputs: Dict[str, Union[torch.Tensor, Any]],
+        prediction_loss_only: bool,
+        ignore_keys: Optional[List[str]] = None,
     ) -> Tuple[Optional[float], Optional[torch.Tensor], Optional[torch.Tensor]]:
         """
         Perform an evaluation step on :obj:`model` using obj:`inputs`.