The full constructor for NotificationsAPI::Notification is implemented
along with the getter methods.
It is now possible to call the elements of Notification in JS without
getting undefined but the default values (or the ones passed in
options).
The method `current_wall_time` is added in EnvironmentSettingsObject.
This passes a least a few more tests because of the getter methods
that are created.
https://wpt.live/notifications/constructor-basic.https.htmlhttps://wpt.live/notifications/idlharness.https.any.html