Race condition on redirect 'Cannot read property 'routes' of undefined'

Nobody has claimed this yet.

Hi and thanks for the library.
But I have an issue 😬

### Description

For example, we have a categories page (lazy module) and when we click on "Categories" link in navigation we want to redirect to default category "Books" (lazy module).
How navigation looks:
Home
— Categories
— Books

The intersection observer emits 3 links sequentially and passes them to requestIdleCallback.

1. Router skips first link '/' because we don't have `loadChildren` property in the router config
2. Router starts loading of a module associated with '/categories' link
3. Strategy doesn't wait until '/categories' loaded and removes '/categories/books' from the list of trees (`this.queue.remove(...)`)

So after `CategoriesModule` loaded strategy doesn't load `BooksModule` .
Last but not least if we go to page 'categories/books' and manually reload the page (cmd + r) we may get the error '*Cannot read property routes of undefined*'. The error is not permanent and more often appears in FireFox and always appears at a slow network (you can get it if setup throttling to 4G in network tab).

### Minimal Reproduction
Repo - [https://github.com/Komock/quick-link-test](https://github.com/Komock/quick-link-test)
Demo - [https://komock.github.io/quick-link-test/](https://komock.github.io/quick-link-test/)

Start with the linked quick-link-test reproduction and reproduce the failure with network throttling, focusing on the sequence involving loadChildren and this.queue.remove(...). Verify the behavior while navigating to categories/books and reloading it; done means both lazy modules load without the routes error.

Written by the indexing model from the issue text.