fix(compiler-cli): add support for more than 2 levels of nested lazy routes

This change adds Compiler CLI support for any level of nesting for lazy routes.

For example `{app-root}/lazy-loaded-module-1/lazy-loaded-module-2/lazy-loaded-module-3`

Where `lazy-loaded-module-3` is lazy loaded from `lazy-loaded-module-2`,
and `lazy-loaded-module-2` is lazy loaded from module `lazy-loaded-module-1`,
and `lazy-loaded-module-1` is lazy loaded from `AppModule`

Fixes angular/angular-cli#3663

modules/@angular/compiler-cli/integrationtest/ngtools_src/feature/lazy-feature.module.ts

@@ -16,7 +16,10 @@ export class LazyFeatureComponent {
 @NgModule({
   imports: [RouterModule.forChild([
     {path: '', component: LazyFeatureComponent, pathMatch: 'full'},
-    {path: 'feature', loadChildren: './feature.module#FeatureModule'}
+    {path: 'feature', loadChildren: './feature.module#FeatureModule'}, {
+      path: 'nested-feature',
+      loadChildren: './lazy-feature-nested.module#LazyFeatureNestedModule'
+    }
   ])],
   declarations: [LazyFeatureComponent]
 })