Bazel runs on newer version of RxJs than is installed in Yarn. The never version subclasses `EmptyError` in a different way which fails the `instanceof` check. This change makes the `instanceof` check more robust with respect to `EmptyError`.
PR Close#21053
* The problem was with the `fireChildActivationStart` function. It was taking a `path` param, which was an
array of `ActivatedRouteSnapshot`s. The function was being fired for each piece of the route that was being
activated. This resulted in far too many `ChildActivationStart` events being fired, and being fired on routes
that weren't actually getting activated. This change fires the event only for those routes that are actually
being activated.
fixes#18942
PR Close#19043
BREAKING CHANGE: the values `true`, `false`, `legacy_enabled` and `legacy_disabled` for the router parameter `initialNavigation` have been removed as they were deprecated. Use `enabled` or `disabled` instead.
PR Close#18781