[Bugfix] Fix mc2 operator error in aclgraph + ep<16 scenario (vllm-project#2609)

### What this PR does / why we need it?
1. quickfix mc2 operator error in aclgraph + ep<16 scenario to recover
CI, will be refactorred in the future
2. disable aclgraph when testing w8a8

### How was this patch tested?
CI passed with existing test.

- vLLM version: v0.10.1.1
- vLLM main:
vllm-project/vllm@9508960

Signed-off-by: MengqingCao <cmq0113@163.com>

Author: MengqingCao

tests/e2e/multicard/test_qwen3_moe.py

@@ -55,6 +55,7 @@ def test_models_distributed_Qwen3_MOE_TP2_WITH_EP():
             tensor_parallel_size=2,
             enable_expert_parallel=True,
             distributed_executor_backend="mp",
+            enforce_eager=False,
     ) as vllm_model:
         vllm_model.generate_greedy(example_prompts, max_tokens)
 
@@ -71,7 +72,7 @@ def test_models_distributed_Qwen3_MOE_W8A8():
             dtype=dtype,
             tensor_parallel_size=2,
             quantization="ascend",
-            enforce_eager=False,
+            enforce_eager=True,
     ) as vllm_model:
         vllm_model.generate_greedy(example_prompts, max_tokens)
 

vllm_ascend/ops/common_fused_moe.py

@@ -242,7 +242,8 @@ def forward_impl(self, hidden_states: torch.Tensor,
         moe_comm_method_name = forward_context.moe_comm_method_name
 
         # TODO: Can we refactor this logic to model_runner?
-        if not self.moe_config.use_ep:
+        # TODO: Adjusted logic to differentiate between A2 and A3, we check ep_size here since mc2 only support ep_size >= 16 on A3 now
+        if self.moe_config.ep_size < 16:
             moe_comm_method_name = "allgathercommimpl"
 
         forward_context.moe_comm_method = getattr(self, moe_comm_method_name)