### What this PR does / why we need it? Optimize the performance of calculation logic in sampler and deepseekv2. ### Does this PR introduce _any_ user-facing change? Added VLLM_ENABLE_TOPK_OPTIMZE config in sampler ### How was this patch tested? pytest test_sampler.py Signed-off-by: wangxiaoxin (A) <wangxiaoxin7@huawei.com> Co-authored-by: wangxiaoxin (A) <wangxiaoxin7@huawei.com> Co-authored-by: ZhengWG <zwg0606@gmail.com>