Add a test for SWR assocation with notifications
The spec says notifications are associated with a service worker registration, and getNotifications() is defined to return notifications "whose service worker registration is this". https://notifications.spec.whatwg.org/#dom-serviceworkerregistration-getnotifications
But in reality WebKit and Gecko instead use scope for that:
- WebKit: https://searchfox.org/wubkat/rev/d477c762a9ecbbc8dedf3ca7a6a2a079577bf60c/Source/WebCore/workers/service/ServiceWorkerRegistration.cpp#351
- Gecko https://searchfox.org/mozilla-central/rev/f19d5bd57655b99f7cd8654674833890c09aed7d/dom/serviceworkers/ServiceWorkerRegistration.cpp#424
while Blink uses registration ID per the spec: https://source.chromium.org/chromium/chromium/src/+/main:third_party/blink/renderer/modules/notifications/service_worker_registration_notifications.cc;l=103-105;drc=b388e927ed4f5c9ef43c899eae909195636af496
This test follows the spec, following the discussion with :asuth.
Differential Revision: https://phabricator.services.mozilla.com/D202612
bugzilla-url: https://bugzilla.mozilla.org/show_bug.cgi?id=1881812
gecko-commit: d7b9a590cbbbb4a0301e1409b95e8ae022e81842
gecko-reviewers: asuth