feat(compiler): generate proper reexports in .ngfactory.ts files to not need transitive deps for compiling .ngfactory.ts files. (#13524)

Note: This checks the constructors of `@Injectable` classes more strictly.
E.g this will fail now as the constructor argument has no `@Inject` nor is
the type of the argument a DI token.

```
@Injectable()
class MyService {
  constructor(dep: string) {}
}
```

Last part of #12787
Closes #12787

modules/@angular/compiler/test/output/js_emitter_spec.ts

@@ -6,6 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
+import {StaticSymbol} from '@angular/compiler/src/aot/static_symbol';
 import {CompileIdentifierMetadata} from '@angular/compiler/src/compile_metadata';
 import {JavaScriptEmitter} from '@angular/compiler/src/output/js_emitter';
 import * as o from '@angular/compiler/src/output/output_ast';
@@ -15,16 +16,17 @@ const someModuleUrl = 'somePackage/somePath';
 const anotherModuleUrl = 'somePackage/someOtherPath';
 
 const sameModuleIdentifier: CompileIdentifierMetadata = {
-  reference: {name: 'someLocalId', filePath: someModuleUrl}
+  reference: new StaticSymbol(someModuleUrl, 'someLocalId', [])
 };
 const externalModuleIdentifier: CompileIdentifierMetadata = {
-  reference: {name: 'someExternalId', filePath: anotherModuleUrl}
+  reference: new StaticSymbol(anotherModuleUrl, 'someExternalId', [])
 };
 
 class SimpleJsImportGenerator implements ImportResolver {
   fileNameToModuleName(importedUrlStr: string, moduleUrlStr: string): string {
     return importedUrlStr;
   }
+  getImportAs(symbol: StaticSymbol): StaticSymbol { return null; }
 }
 
 export function main() {
@@ -33,11 +35,13 @@ export function main() {
   // - declaring fields
 
   describe('JavaScriptEmitter', () => {
+    let importResolver: ImportResolver;
     let emitter: JavaScriptEmitter;
     let someVar: o.ReadVarExpr;
 
     beforeEach(() => {
-      emitter = new JavaScriptEmitter(new SimpleJsImportGenerator());
+      importResolver = new SimpleJsImportGenerator();
+      emitter = new JavaScriptEmitter(importResolver);
       someVar = o.variable('someVar');
     });
 
@@ -124,6 +128,16 @@ export function main() {
       ].join('\n'));
     });
 
+    it('should support `importAs` for external identifiers', () => {
+      spyOn(importResolver, 'getImportAs')
+          .and.returnValue(new StaticSymbol('somePackage/importAsModule', 'importAsName', []));
+      expect(emitStmt(o.importExpr(externalModuleIdentifier).toStmt())).toEqual([
+        `var import0 = re` +
+            `quire('somePackage/importAsModule');`,
+        `import0.importAsName;`
+      ].join('\n'));
+    });
+
     it('should support operators', () => {
       const lhs = o.variable('lhs');
       const rhs = o.variable('rhs');