fix: element injector vs module injector (#15044)

fixes #12869
fixes #12889
fixes #13885
fixes #13870

Before this change there was a single injector tree.
Now we have 2 injector trees, one for the modules and one for the components.
This fixes lazy loading modules.

See the design docs for details:
https://docs.google.com/document/d/1OEUIwc-s69l1o97K0wBd_-Lth5BBxir1KuCRWklTlI4

BREAKING CHANGES

`ComponentFactory.create()` takes an extra optional `NgModuleRef` parameter.
No change should be required in user code as the correct module will be used
when none is provided

DEPRECATIONS

The following methods were used internally and are no more required:
- `RouterOutlet.locationFactoryResolver`
- `RouterOutlet.locationInjector`

packages/core/test/application_ref_spec.ts

@@ -6,7 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {APP_BOOTSTRAP_LISTENER, APP_INITIALIZER, CompilerFactory, Component, NgModule, NgZone, PlatformRef, TemplateRef, Type, ViewChild, ViewContainerRef} from '@angular/core';
+import {APP_BOOTSTRAP_LISTENER, APP_INITIALIZER, Compiler, CompilerFactory, Component, NgModule, NgZone, PlatformRef, TemplateRef, Type, ViewChild, ViewContainerRef} from '@angular/core';
 import {ApplicationRef, ApplicationRef_} from '@angular/core/src/application_ref';
 import {ErrorHandler} from '@angular/core/src/error_handler';
 import {ComponentRef} from '@angular/core/src/linker/component_factory';
@@ -72,6 +72,33 @@ export function main() {
       return MyModule;
     }
 
+    it('should bootstrap a component from a child module',
+       async(inject([ApplicationRef, Compiler], (app: ApplicationRef, compiler: Compiler) => {
+         @Component({
+           selector: 'bootstrap-app',
+           template: '',
+         })
+         class SomeComponent {
+         }
+
+         @NgModule({
+           providers: [{provide: 'hello', useValue: 'component'}],
+           declarations: [SomeComponent],
+           entryComponents: [SomeComponent],
+         })
+         class SomeModule {
+         }
+
+         createRootEl();
+         const modFactory = compiler.compileModuleSync(SomeModule);
+         const module = modFactory.create(TestBed);
+         const cmpFactory = module.componentFactoryResolver.resolveComponentFactory(SomeComponent);
+         const component = app.bootstrap(cmpFactory);
+
+         // The component should see the child module providers
+         expect(component.injector.get('hello')).toEqual('component');
+       })));
+
     describe('ApplicationRef', () => {
       beforeEach(() => { TestBed.configureTestingModule({imports: [createModule()]}); });