Fix integration with Accelerate and failing test (#24691)

Fix integration

src/transformers/trainer.py

@@ -3176,13 +3176,19 @@ class Trainer:
 
         # Gather all remaining tensors and put them back on the CPU
         if losses_host is not None:
-            all_losses = nested_numpify(losses_host)
+            losses = nested_numpify(losses_host)
+            all_losses = losses if all_losses is None else np.concatenate((all_losses, losses), axis=0)
         if preds_host is not None:
-            all_preds = nested_numpify(preds_host)
+            logits = nested_numpify(preds_host)
+            all_preds = logits if all_preds is None else nested_concat(all_preds, logits, padding_index=-100)
         if inputs_host is not None:
-            all_inputs = nested_numpify(inputs_host)
+            inputs_decode = nested_numpify(inputs_host)
+            all_inputs = (
+                inputs_decode if all_inputs is None else nested_concat(all_inputs, inputs_decode, padding_index=-100)
+            )
         if labels_host is not None:
-            all_labels = nested_numpify(labels_host)
+            labels = nested_numpify(labels_host)
+            all_labels = labels if all_labels is None else nested_concat(all_labels, labels, padding_index=-100)
 
         # Number of samples
         if has_length(eval_dataset):