refactor(cdk-experimental/scrolling): switch to standalone

Reworks `cdk-experimental/scrolling` to support standalone.

Author: crisbeto

src/cdk-experimental/scrolling/auto-size-virtual-scroll.ts

@@ -462,6 +462,7 @@ export function _autoSizeVirtualScrollStrategyFactory(autoSizeDir: CdkAutoSizeVi
       deps: [forwardRef(() => CdkAutoSizeVirtualScroll)],
     },
   ],
+  standalone: true,
 })
 export class CdkAutoSizeVirtualScroll implements OnChanges {
   /**

src/cdk-experimental/scrolling/scrolling-module.ts

@@ -10,7 +10,7 @@ import {NgModule} from '@angular/core';
 import {CdkAutoSizeVirtualScroll} from './auto-size-virtual-scroll';
 
 @NgModule({
+  imports: [CdkAutoSizeVirtualScroll],
   exports: [CdkAutoSizeVirtualScroll],
-  declarations: [CdkAutoSizeVirtualScroll],
 })
 export class ScrollingModule {}

src/cdk-experimental/scrolling/virtual-scroll-viewport.spec.ts

@@ -11,8 +11,7 @@ describe('CdkVirtualScrollViewport', () => {
 
     beforeEach(waitForAsync(() => {
       TestBed.configureTestingModule({
-        imports: [ScrollingModule, ExperimentalScrollingModule],
-        declarations: [AutoSizeVirtualScroll],
+        imports: [ScrollingModule, ExperimentalScrollingModule, AutoSizeVirtualScroll],
       }).compileComponents();
     }));
 
@@ -94,6 +93,8 @@ function finishInit(fixture: ComponentFixture<any>) {
   `,
   ],
   encapsulation: ViewEncapsulation.None,
+  standalone: true,
+  imports: [ScrollingModule, ExperimentalScrollingModule],
 })
 class AutoSizeVirtualScroll {
   @ViewChild(CdkVirtualScrollViewport, {static: true}) viewport: CdkVirtualScrollViewport;