feat(ivy): support for the ngForOf directive, with tests (#21430)

Implement NgOnChangesFeature, ViewContainerRef, TemplateRef,
and the renderEmbeddedTemplate instruction, and wire together the
pieces required for the ngForOf directive to work.

PR Close #21430

packages/core/src/render3/interfaces/container.ts

@@ -66,6 +66,13 @@ export interface LContainer {
    * The template extracted from the location of the Container.
    */
   readonly template: ComponentTemplate<any>|null;
+
+
+  /**
+   * A count of dynamic views rendered into this container. If this is non-zero, the `views` array
+   * will be traversed when refreshing dynamic views on this container.
+   */
+  dynamicViewCount: number;
 }
 
 /**