Add an event for test completed.

Useful for simplifying some checks.
Notify reporters when a test is done.
Fix sloppy code.
Fire the health.check.test.completed event.
Create a default testCompleted implementation.
Remember to extend Reporter ...
Simplify the console table reporter.
Remove error trap from service.

Another subscriber can do the work.
Create an interface for file reporter(s).
First swipe at a generic FileReporter.

isTemporary is only available for convenience of the caller.
Create a statistics reporter.