refactor(ivy): revert onChanges change back to a feature (#28187)

- adds fixmeIvy annotation to tests that should remain updated so we can resolve those issues in the subsequent commits

PR Close #28187

packages/core/src/interface/lifecycle_hooks.ts

@@ -5,9 +5,19 @@
  * Use of this source code is governed by an MIT-style license that can be
  * found in the LICENSE file at https://angular.io/license
  */
-import {SimpleChanges} from './simple_change';
+import {SimpleChanges, SimpleChange} from './simple_change';
 
 
+/**
+ * Defines an object that associates properties with
+ * instances of `SimpleChange`.
+ *
+ * @see `OnChanges`
+ *
+ * @publicApi
+ */
+export interface SimpleChanges { [propName: string]: SimpleChange; }
+
 /**
  * @description
  * A lifecycle hook that is called when any data-bound property of a directive changes.