changed option

[jfgreffier]

Run tests that are uncommited , or have changes compared to a commit.

npx playwright test --changed
npx playwright test --changed d819f97f40386c9bd31a53525240c6e9997a10f4
npx playwright test --changed main

Can also be passed in TestConfig

• 'main' - run new tests e.g. from a Pull Request
• true - run tests with uncommited changes
• 'HEAD~1' - run tests new compared to the last commit

Fixes #15075