Folio 0.3.17 doesn't differentiate between expected and unexpected
flakiness, thus no longer supporting the "flaky" annotation.
Flaky specs are reported after run, but flaky specs do not render
test run as failed. We'll track flakiness separately via a dashboard.
This is a large rework of selectors:
- Each BrowserContext now has a separate Selectors instance that has its own registrations.
Most of them share a single sharedSelectors instance, but contexts created for a connected
browser have their own instance.
- Connected browser now gets a RemoteBrowser object that encapsulates Selectors and Browser.
This Selectors object is registered with the api selectors.
- Public selectors.register api iterates over all registered Selectors channels
and registers in each of them.
- createSelector testing method migrated to ElementHandle._createSelectorForTest.
