…per (#40029) (#40315)

When stepping through the `recognize` algorithm, it is much easier to
follow when using a simple `for...of` rather than the helper
`mapChildrenIntoArray` with the passed closure. The only special thing that
`mapChildrenIntoArray` does is ensure the primary route appears first.
This change will have no affect on the result because `processChildren` later calls
`sortActivatedRouteSnapshots`, which does the same thing.

PR Close #40029

PR Close #40315

…o match (#40029) (#40315)

This commit updates the `recognize` algorithm to return `null` when a
segment does not match a given config rather than throwing an error.
This makes the code much easier to follow because the "no match" result
has to be explicitly handled rather than catching the error in very
specific places.

PR Close #40029

PR Close #40315

To make the tests suite easier to follow, `Recognize#apply` can be made
into a synchronous function rather than one that return an `Observable`.

Also, as a chore, remove as many `any` types as possible.

PR Close #40029

PR Close #40315

…zed (#40029) (#40315)

This commit updates the `recognize` algorithm to work with named outlets
which have empty path parents. For example, given the following config

```
  const routes = [
    {
      path: '',
      children: [
        {path: 'a', outlet: 'aux', component: AuxComponent}
    ]}
  ];
```

The url `/(aux:a)` should match this config. In order to do so, we need
to allow the children of `UrlSegmentGroup`s to match a `Route` config
for a different outlet (in this example, the `primary`) when it's an
empty path. This should also *only* happen if we were unable to find a
match for the outlet in the level above. That is, the matching strategy
is to find the first `Route` in the list which _matches the given
outlet_. If we are unable to do that, then we allow empty paths from
other outlets to match and try to find some child there whose outlet
matches our segment.

PR Close #40029

PR Close #40315

… (#40315)

The `applyRedirects` and `recognize` algorithms have the same overall goal:
match a `UrlTree` with the application's `Routes` config. There are a
few key functions in these algorithms which can be shared rather than
duplicated between the two. This also makes it easier to see how the two
are similar and where they diverge.

PR Close #40029

PR Close #40315

…th parents (#40029) (#40315)

There are two parts to this commit:
1. Revert the changes from #38379. This change had an incomplete view of
how things worked and also diverged the implementations of
`applyRedirects` and `recognize` even more.
2. Apply the fixes from the `recognize` algorithm to ensure that named
outlets with empty path parents can be matched. This change also passes
all the tests that were added in #38379 with the added benefit of being
a more complete fix that stays in-line with the `recognize` algorithm.
This was made possible by using the same approach for `split` by
always creating segments for empty path matches (previously, this was
only done in `applyRedirects` if there was a `redirectTo` value). At the
end of the expansions, we need to squash all empty segments so that
serializing the final `UrlTree` returns the same result as before.

Fixes #39952
Fixes #10726
Closes #30410

PR Close #40029

PR Close #40315