[benchmark][structured output] Add offline benchmark script for structured output

[lk-chen]

• Reuse some flags from serving version
• Tested that serving benchmark still work in V0
  • V1 serving benchmark is broken, but it was already broken on main branch
• Tested that offline benchmark work in V0/V1
• updated run_structured_ouput_benchmark.sh to allow config QPS_VALUES

[github-actions]

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[mergify]

This pull request has merge conflicts that must be resolved before it can be
merged. Please rebase the PR, @lk-chen.

https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/working-with-forks/syncing-a-fork

[mergify]

⚠️ The sha of the head commit of this PR conflicts with #17440. Mergify cannot evaluate rules on this PR. ⚠️