refactor(core): Move private export testing file to src (#55103)

This matches the private export approach for files in other packages.

PR Close #55103

packages/core/testing/public_api.ts

@@ -14,6 +14,5 @@
  * Entry point for all public APIs of this package.
  */
 export * from './src/testing';
-export * from './private_export';
 
 // This file only reexports content of the `src` folder. Keep it that way.

packages/core/testing/private_export.ts → packages/core/testing/src/private_export.ts

@@ -6,4 +6,4 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-export {AllowDetectChangesAndAcknowledgeItCanHideApplicationBugs as ɵAllowDetectChangesAndAcknowledgeItCanHideApplicationBugs} from './src/test_bed_common';
+export {AllowDetectChangesAndAcknowledgeItCanHideApplicationBugs as ɵAllowDetectChangesAndAcknowledgeItCanHideApplicationBugs} from './test_bed_common';

packages/core/testing/src/testing.ts

@@ -12,6 +12,7 @@
  * Entry point for all public APIs of the core/testing package.
  */
 
+export * from './private_export';
 export * from './async';
 export {ComponentFixture} from './component_fixture';
 export {resetFakeAsyncZone, discardPeriodicTasks, fakeAsync, flush, flushMicrotasks, tick} from './fake_async';