unskip carousel e2e tests

Author: erwinmombay

extensions/amp-base-carousel/0.1/test-e2e/test-arrows-non-looping.js

@@ -31,21 +31,18 @@ describes.endtoend(
       nextArrow = await getNextArrow(controller);
     });
 
-    // TODO(#40214): fix flaky test.
-    it.skip('should have the arrows in the correct initial state', async () => {
+    it('should have the arrows in the correct initial state', async () => {
       await expect(css(prevArrow, 'opacity')).to.equal('0');
       await expect(css(nextArrow, 'opacity')).to.equal('1');
     });
 
-    // TODO(#40214): fix flaky test.
-    it.skip('should show the prev arrow when going to the first slide', async () => {
+    it('should show the prev arrow when going to the first slide', async () => {
       await controller.click(nextArrow);
       await expect(css(prevArrow, 'opacity')).to.equal('1');
       await expect(css(nextArrow, 'opacity')).to.equal('1');
     });
 
-    // TODO(#40214): fix flaky test.
-    it.skip('should hide the next arrow when going to the end', async () => {
+    it('should hide the next arrow when going to the end', async () => {
       const el = await getScrollingElement(controller);
       await controller.scrollTo(el, {left: (SLIDE_COUNT - 1) * pageWidth});