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