[2/4][Refactor] Refactor torchair utils (#1892)

There is a lot torchair specified logic in common code. It results hard
code maintenance. We will create a new torchair module to launch
torchair related logic there. I plan to add 4 PR.

1. Refactor worker
2. Refactor utils (this PR)
- simple change that move all torchair related util function to torchair
module
3. Refactor model_runner
4. Refactor attention

- vLLM version: v0.9.2
- vLLM main:
8188196a1c

Signed-off-by: wangxiyuan <wangxiyuan1007@gmail.com>

vllm_ascend/ops/fused_moe.py

@@ -43,10 +43,10 @@ from vllm_ascend.ascend_config import get_ascend_config
 from vllm_ascend.distributed.communication_op import \
     data_parallel_reduce_scatter
 from vllm_ascend.ops.expert_load_balancer import ExpertLoadBalancer
+from vllm_ascend.torchair.utils import npu_stream_switch, npu_wait_tensor
 from vllm_ascend.utils import (FusedMoEState, dispose_tensor,
                                get_all_reduce_merge_state, get_fused_moe_state,
-                               get_rm_router_logits_state, is_310p,
-                               npu_stream_switch, npu_wait_tensor)
+                               get_rm_router_logits_state, is_310p)
 
 MOE_ALL2ALL_BUFFER: bool = envs_ascend.MOE_ALL2ALL_BUFFER
 SELECT_GATING_TOPK_SOTFMAX_EXPERTS: bool = envs_ascend.SELECT_GATING_TOPK_SOTFMAX_EXPERTS