[hotfix] use the original implementation in 8785 (#8994)

python/sglang/srt/layers/communicator.py

@@ -553,6 +553,10 @@ class CommunicateSummableTensorPairFn:
             forward_batch.gathered_buffer[: forward_batch.input_ids.shape[0]],
             hidden_states,
         )
+
+        if hidden_states.data_ptr() is global_hidden_states.data_ptr():
+            hidden_states = torch.empty_like(hidden_states)
+
         if allow_reduce_scatter and forward_batch.dp_padding_mode.is_max_len():
             # When using padding, all_reduce is skipped after MLP and MOE and reduce scatter is used here instead.
             dp_reduce_scatter_tensor(hidden_states, global_hidden_states)