tests(react): create tests for the react bindings to core (#17551)

* Add tests.

* updates after API meeting.

* test(): add tests for create controller components.

* correct testing for controller component

* Ensure tests properly cleanup after each run.

* create common test utils for overlay and controllers.

* initial tests for ion router outlet

* simple update.

* add mocks for jest tests.

react/__mocks__/ionicons/index.js

@@ -0,0 +1,2 @@
+
+exports.addIcons = () => {};