### What this PR does / why we need it?
Add test_qwen3_5.py for base scenarios tp4 on Qwen3.5-27B and
Qwen3.5-35B-A3B.
- vLLM version: main
- vLLM main:
4034c3d32e
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Signed-off-by: pppeng <zepengliu912@qq.com>
Co-authored-by: Mengqing Cao <cmq0113@163.com>