Fix shape error detected by benchmark

Signed-off-by: Chendi.Xue <[email protected]>

vllm/sequence.py

@@ -1182,7 +1182,8 @@ def update(self,
                second_last_token_hidden_states: Optional[torch.Tensor] = None):
         """Update hidden states from target model invocation. Only used for
         decode steps"""
-        assert len(seq_group_metadata_list) == len(hidden_states)
+        if len(seq_group_metadata_list) < len(hidden_states):
+            hidden_states = hidden_states[:len(seq_group_metadata_list)]
         self._seq_ids.extend(get_all_seq_ids(seq_group_metadata_list))
         self.hidden_states = torch.cat([self.hidden_states, hidden_states])