Change model output parameter to last_hidden_states for IPEXModel (#589)

* change model output parameter to last_hidden_states

* update ipex model testiong

* update testing

* add output name to ipex model

Author: jiqing-feng

optimum/intel/ipex/modeling_base.py

@@ -58,6 +58,7 @@ class IPEXModel(OptimizedModel):
     export_feature = "feature-extraction"
     base_model_prefix = "ipex_model"
     main_input_name = "input_ids"
+    output_name = "last_hidden_state"
 
     def __init__(
         self,
@@ -193,7 +194,12 @@ def forward(
             inputs["token_type_ids"] = token_type_ids
 
         outputs = self._call_model(**inputs)
-        return ModelOutput(**outputs) if isinstance(outputs, dict) else ModelOutput(logits=outputs[0])
+        if isinstance(outputs, dict):
+            model_output = ModelOutput(**outputs)
+        else:
+            model_output = ModelOutput()
+            model_output[self.output_name] = outputs[0]
+        return model_output
 
     def eval(self):
         self.model.eval()
@@ -235,16 +241,19 @@ def _init_warmup(self):
 class IPEXModelForSequenceClassification(IPEXModel):
     auto_model_class = AutoModelForSequenceClassification
     export_feature = "text-classification"
+    output_name = "logits"
 
 
 class IPEXModelForTokenClassification(IPEXModel):
     auto_model_class = AutoModelForTokenClassification
     export_feature = "token-classification"
+    output_name = "logits"
 
 
 class IPEXModelForMaskedLM(IPEXModel):
     auto_model_class = AutoModelForMaskedLM
     export_feature = "fill-mask"
+    output_name = "logits"
 
 
 class IPEXModelForImageClassification(IPEXModel):