MediaPlayerThumbnail.update is assynchron and fires 'updated' message.
MediaPlayerThumbnailsBar.update() is assynchron, wait for all
Thumbnail.update() and fires 'updated' event.
Set JsTestCase.state to TEARDOWN before calling afterEachTests() method.
Add JsTestClass.currentTestCase attribute.
Add BrowserWidget.finalizeRevertConstruction() method.
Add 'componentName' attribute.
Add MediaPlayerWidget.onDisplayConstructionError() method.
Turn MediaPlayerWidget.afterEachTest() to asynchron.