[Feat] enable hierarchical communication for mc2 ops on A2 (#3015)

Currently, when in A2, setting the environment variables
`HCCL_INTRA_PCIE_ENABLE=1` and `HCCL_INTRA_ROCE_ENABLE=0` can reduce
cross-machine communication traffic and significantly improve
communication performance.

For more details, please refer to
[document](https://www.hiascend.com/document/detail/zh/Pytorch/710/apiref/torchnpuCustomsapi/context/torch_npu-npu_moe_distribute_dispatch_v2.md)

- vLLM version: v0.11.0rc3
- vLLM main: https://github.com/vllm-project/vllm/commit/v0.11.0

---------

Signed-off-by: realliujiaxu <realliujiaxu@163.com>

tests/ut/ops/test_token_dispatcher.py

@@ -92,7 +92,8 @@ class TestTokenDispatcherWithMC2(TestBase):
         expert_map = torch.tensor([0, 1, 2, 3, 4, 5, 6, 7])
 
         with patch("torch_npu.npu_moe_distribute_dispatch_v2",
-                   return_value=(torch.randn(10, 128), ) * 5) as mock_dispatch:
+                   return_value=(torch.randn(10, 128), ) * 5 +
+                   (None, None)) as mock_dispatch:
             output = self.dispatcher.token_dispatch(hidden_states,
                                                     topk_weights, topk_ids,
                                                     self.row_idx, expert_map)
@@ -112,7 +113,7 @@ class TestTokenDispatcherWithMC2(TestBase):
         self.topk_weights = torch.randn(10, 1)
 
         with patch("torch_npu.npu_moe_distribute_dispatch_v2",
-                   return_value=(torch.randn(10, 128), ) * 5):
+                   return_value=(torch.randn(10, 128), ) * 5 + (None, None)):
             self.dispatcher.token_dispatch(self.hidden_states,
                                            self.topk_weights,
                                            torch.randint(0, 8, (10, 1)),