[Feature]: allow specifying how many tests to run based on count and offset. #38598
Description
🚀 Feature Request
It would be fantastic if we could specify how many tests to run, as well as an optional offset.
Example
Run 100/$total tests
npx playwright --execute 100
Run 100/$total tests, starting from 50th test
npx playwright --execute 100,50
Motivation
sharding is great for when test takes a similar amount of time to run, as they should on an ideal world. However, this can be far from reality and using sharing to spread tests across multiple CI/CD containers to compensate this issue can get quite complex.