Add early stop in pool.

[yuxuan-ms]

Bug / Requirement Description

Clearly and concisely describe the problem.

Solution description

Describe your code changes in detail for reviewers.

Checklist:

• [ ] Test
• [ ] Example (both test_plan.py and .rst)
• [ ] Documentation (API)
• [ ] News fragment present for release notes
• [ ] MS info leakage check
• [ ] For new driver: driver index page
• [ ] For new assertion: ui/pdf/std renderers, documentation
• [ ] For new cmdline arg: documentation