build: TypeScript 3.5 upgrade (#31615)

https://github.com/Microsoft/TypeScript/wiki/Breaking-Changes#typescript-35

PR Close #31615

packages/core/src/event_emitter.ts

@@ -56,7 +56,7 @@ import {Subject, Subscription} from 'rxjs';
  *
  * @publicApi
  */
-export class EventEmitter<T> extends Subject<T> {
+export class EventEmitter<T extends any> extends Subject<T> {
   // TODO: mark this as internal once all the facades are gone
   // we can't mark it as internal now because EventEmitter exported via @angular/core would not
   // contain this property making it incompatible with all the code that uses EventEmitter via

packages/core/src/linker/element_ref.ts

@@ -24,7 +24,7 @@ import {noop} from '../util/noop';
 // Note: We don't expose things like `Injector`, `ViewContainer`, ... here,
 // i.e. users have to ask for what they need. With that, we can build better analysis tools
 // and could do better codegen in the future.
-export class ElementRef<T = any> {
+export class ElementRef<T extends any = any> {
   /**
    * The underlying native element or `null` if direct access to native elements is not supported
    * (e.g. when the application runs in a web worker).