This was historically done to make `console.log()` have colors. However,
this makes any other code that checks `process.stdout.isTTY` incorrectly
assume real TTY support.
Node18 and Node20 now respect `FORCE_COLOR=1` in console, so our default
behavior of forcing colors in the worker process just works out of the
box. See https://github.com/nodejs/node/pull/48034.
- `stdout.isTTY` controls whether list reporter updates lines or just adds them;
- `env.CI` is used in a few places to affect the defaults:
- whether to open interactive html;
- default reporter dot/line;
- default terminal reporter added to non-terminal reporters;
- `env.PWTEST_SKIP_TEST_OUTPUT` is removed;
- `env.PW_TEST_DEBUG_REPORTERS` is introduced specifically for tests.
- 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.
