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
3966bcc5d9