When loading a module that doesn't provide `RouterModule.forChild()` preloader will get stuck
in an infinite loop and throw `ERROR Error: Maximum call stack size exceeded.`
The issue is that child module's `Injector` will look to its parent `Injector` when it doesn't
find any `ROUTES` so it will return routes for it's parent module instead. This will load the
child again that returns its parent's routes and so on.
Closes#29164
PR Close#36605
b37a9eba1a