This hook is `cancel()`'d in a willTransition hook, but that isn't always enough. It might still be scheduled if there is a scroll event between `willTransition`, and the transition actually completing. Following c2d94be06e4fffec1b333881046c293d5e39beb5, this kind of scroll event happens when the loading indicator is set to 'spinner'. This would put the router in a weird state and cause navigation issues.
Also takes the opportunity to remove JQuery from this code path
https://meta.discourse.org/t/286463/15
86f3e86596