* Add basic testing for ServiceWorkerGlobalScope.registration

Received updatefound event on self.registration
Received install event
* self.registration
scope: http://127.0.0.1:8000/workers/service/resources/
updateViaCache: imports
installing worker:
- scriptURL: http://127.0.0.1:8000/workers/service/resources/self_registration-worker.js
- state: installing
waiting worker: null
active worker: null

Received statechange event on service worker
Received statechange event on service worker
Received activate event
* self.registration
scope: http://127.0.0.1:8000/workers/service/resources/
updateViaCache: imports
installing worker: null
waiting worker: null
active worker:
- scriptURL: http://127.0.0.1:8000/workers/service/resources/self_registration-worker.js
- state: activating

Received statechange event on service worker
* self.registration
scope: http://127.0.0.1:8000/workers/service/resources/
updateViaCache: imports
installing worker: null
waiting worker: null
active worker:
- scriptURL: http://127.0.0.1:8000/workers/service/resources/self_registration-worker.js
- state: activated