[Qwen-moe] Remove the minor operation arange (#2373)

### What this PR does / why we need it?
Integrate the arange operator to reduce the time spent and improve
performance

### Does this PR introduce _any_ user-facing change?
No

### How was this patch tested?

- vLLM version: v0.10.1.1
- vLLM main:
56dcf4e7e9

---------

Signed-off-by: s30076806 <songjiayang2@h-partners.com>

tests/ut/ops/test_fused_ops.py

@@ -405,7 +405,7 @@ class TestExpertsSelector:
 
         x = torch.randn(8, 2)
         router_logits = torch.randn(8, 2)
-        topk_weights, topk_ids = select_experts(
+        topk_weights, topk_ids, _ = select_experts(
             hidden_states=x,
             router_logits=router_logits,
             top_k=2,