Service runner registers a bunch of SIG* listeners when the service is started and does not remove them when it's stopped. I production this doesn't matter, however within the tests we start/stop the server all the time which leads to annoying warnings being emitted. We need to clear the sig handlers when the server is stopped.

Acceptance criteria: running RESTBase tests with a modified service-runner package and not seeing logged warnings for EventEmitter maxListeners exceeded.