test(compiler-cli): load type declarations from fake_common (#41995)

The ngtsc test targets have fake declarations files for `@angular/core`
and `@angular/common` and the template type checking tests can leverage
the fake common declarations instead of declaring its own types.

PR Close #41995

packages/compiler-cli/src/ngtsc/testing/fake_common/index.ts

@@ -56,6 +56,7 @@ export declare class NgIf<T = unknown> {
     'ngIfElse': 'ngIfElse';
   }
   , {}, never > ;
+  static ngTemplateGuard_ngIf: 'binding';
   static ngTemplateContextGuard<T>(dir: NgIf<T>, ctx: any):
       ctx is NgIfContext<Exclude<T, false|0|''|null|undefined>>;
 }
@@ -83,8 +84,16 @@ export declare class DatePipe {
   static ɵpipe: ɵɵPipeDeclaration<DatePipe, 'date'>;
 }
 
+export declare class IndexPipe {
+  transform<T>(value: T[], index: number): T;
+
+  static ɵpipe: ɵɵPipeDeclaration<IndexPipe, 'index'>;
+}
+
 export declare class CommonModule {
   static ɵmod: ɵɵNgModuleDeclaration<
-      CommonModule, [typeof NgForOf, typeof NgIf, typeof DatePipe, typeof NgTemplateOutlet], never,
-      [typeof NgForOf, typeof NgIf, typeof DatePipe, typeof NgTemplateOutlet]>;
+      CommonModule,
+      [typeof NgForOf, typeof NgIf, typeof DatePipe, typeof IndexPipe, typeof NgTemplateOutlet],
+      never,
+      [typeof NgForOf, typeof NgIf, typeof DatePipe, typeof IndexPipe, typeof NgTemplateOutlet]>;
 }