This fixes two issues:
- Sudden worker process exit is properly accounted for.
- We can stop() workers willy-nilly, e.g. after reaching maxFailures.
Details:
- DonePayload does not send `reamining` anymore, and worker does not track it.
- Instead, `Dispatcher._runJob` track remaining tests and acts accordingly.
- Upon worker exit, we emulate a fatal error for all remaining tests.
Drive-by:
- Do not report onTestBegin after reaching maxFailures to avoid confusion.
Before, we did report onTestBegin, but not onTestEnd.
- List reporter aligned between "running" and "finished" state - it was
one character misplaced.
- Added a SIGINT test.
