What this PR does / why we need it? test vllm_ascend/envs.py contains environment variables defination Does this PR introduce any user-facing change? N/A How was this patch tested? CI passed with new added test. vLLM version: v0.10.0 vLLM main:9532a6d563- vLLM version: v0.10.0 - vLLM main:b4e081cb15--------- Signed-off-by: chengyuan <chengyuan27@huawei.com> Co-authored-by: chengyuan <chengyuan27@huawei.com>