test: Disable flaky test on Chromecast (#8381)

Author: avelad

test/offline/storage_playback_integration.js

@@ -166,6 +166,11 @@ filterDescribe('Storage', checkStorageSupport, () => {
   });
 
   it('supports MSS download and playback', async () => {
+    // This tests is flaky in some Chromecast devices, so we need omit it
+    // for now.
+    if (shaka.util.Platform.isChromecast()) {
+      pending('Disabled on Chromecast.');
+    }
     const url = '/base/test/test/assets/mss-clear/Manifest';
     const metadata = {
       'title': 'MSS',