refactor(cdk/scrolling): switch tests away from fakeAsync (#33150)

Reworks the CDK scrolling tests not to depend on `fakeAsync` anymore.

Author: crisbeto

src/cdk/scrolling/scroll-dispatcher.spec.ts

@@ -1,4 +1,4 @@
-import {TestBed, fakeAsync, ComponentFixture, tick} from '@angular/core/testing';
+import {TestBed, ComponentFixture} from '@angular/core/testing';
 import {Component, ViewChild, ElementRef, ChangeDetectionStrategy} from '@angular/core';
 import {CdkScrollable, ScrollDispatcher, ScrollingModule} from './public-api';
 import {dispatchFakeEvent} from '../testing/private';
@@ -31,7 +31,7 @@ describe('ScrollDispatcher', () => {
       expect(scroll.scrollContainers.has(componentScrollable)).toBe(false);
     });
 
-    it('should notify through the directive and service that a scroll event occurred', fakeAsync(() => {
+    it('should notify through the directive and service that a scroll event occurred', async () => {
       // Listen for notifications from scroll directive
       const scrollable = fixture.componentInstance.scrollable;
       const directiveSpy = jasmine.createSpy('directive scroll callback');
@@ -55,9 +55,9 @@ describe('ScrollDispatcher', () => {
       expect(serviceSpy).not.toHaveBeenCalled();
 
       // After the throttle time, the notification should be sent.
-      tick(throttleTime);
+      await new Promise(resolve => setTimeout(resolve, throttleTime + 10));
       expect(serviceSpy).toHaveBeenCalled();
-    }));
+    });
 
     it('should be able to unsubscribe from the global scrollable', () => {
       const spy = jasmine.createSpy('global scroll callback');

src/cdk/scrolling/viewport-ruler.spec.ts

@@ -1,4 +1,4 @@
-import {TestBed, fakeAsync, tick} from '@angular/core/testing';
+import {TestBed} from '@angular/core/testing';
 import {dispatchFakeEvent} from '../testing/private';
 import {ViewportRuler} from './viewport-ruler';
 
@@ -109,17 +109,17 @@ describe('ViewportRuler', () => {
       subscription.unsubscribe();
     });
 
-    it('should be able to throttle the callback', fakeAsync(() => {
+    it('should be able to throttle the callback', async () => {
       const spy = jasmine.createSpy('viewport changed spy');
-      const subscription = viewportRuler.change(1337).subscribe(spy);
+      const subscription = viewportRuler.change(10).subscribe(spy);
 
       dispatchFakeEvent(window, 'resize');
       expect(spy).not.toHaveBeenCalled();
 
-      tick(1337);
+      await new Promise(resolve => setTimeout(resolve, 20));
 
       expect(spy).toHaveBeenCalledTimes(1);
       subscription.unsubscribe();
-    }));
+    });
   });
 });