Two bug fixes:
- Do not use the worker that is being shutdown for a new job.
- Report unhandled errors during "expected to fail" tests as
fatal errors.
This fixes an issue where we incorrectly labeled and assigned ids for tests
that declared tests in require'd files or used test wrappers.
See new tests for examples.
- Source now lives at `src/test`.
- Former folio tests live at `tests/playwright-test`.
- We use `src/test/internal.ts` that exposes base test without
Playwright fixtures for most tests (to avoid modifications for now).
- Test types live in `types/testFoo.d.ts`.
- Stable test runner is installed to `tests/config/test-runner` during `npm install`.
- All deps including test-only are now listed in `package.json`.
Non-test deps must also be listed in `build_package.js` to get included.
