[Feature]: add a custom --after filter for test execution

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### 🚀 Feature Request

Add support for a CLI flag that allows users to run only the tests discovered after a specified test name, while preserving the existing parallel/serial test runner behavior.

Example:
`npx playwright test --after "login"`

This should run only the tests that appear after the matching test in the discovered test order, without running earlier tests.

### Example

Currently, Playwright supports selecting tests by file or grep, but it does not provide a way to select a subset based on execution order relative to another test. This is useful in workflows where:

- a setup or prerequisite test must run first
- a user wants to rerun only the remaining tests after a known checkpoint
- a large suite is being debugged incrementally

Proposed behavior
Add a new CLI option:

`--after `

Behavior:

- Playwright discovers all tests in the configured order
- it finds the matching test name
- it removes all tests before that match
- it schedules only the remaining tests for execution
- the remaining tests can still be distributed across workers in parallel/serial mode

This means the flag acts as a pre-distribution filter, not as a strict runtime dependency.

Example:

If the discovered order is:

- setup
- login
- checkout
- payment
- logout

Then:
`npx playwright test --after "login"`

should run:
- checkout
- payment
- logout
and not setup or login.

### Motivation

This gives users a lightweight way to:
- continue execution from a known stage
- rerun only post-setup flow
- reduce debugging time for large test suites
- avoid editing files or test names just to select a subset

Start at Playwright's test CLI option handling and follow how discovered tests are filtered before worker distribution. Check the existing test-selection and parallel/serial runner tests first; done means --after excludes the named test and all earlier tests while preserving the remaining execution behavior.

Written by the indexing model from the issue text.