Need to add a delay between calls to `createDriver` and `driver.get`

In DartPad, webdriver tests are failing unless an artificial delay is added:

```dart
setUp(() async {
// Connect to it with the webdriver package
driver = await createDriver(
uri: Uri.parse('http://localhost:4444/wd/hub/'),
desired: Capabilities.chrome);

await Future.delayed(Duration(milliseconds: 2000));

// Go to your page
await driver.get('http://localhost:8000/');
await waitForPageToStabilize();
});
```

https://github.com/dart-lang/dart-pad/issues/2360
https://github.com/dart-lang/dart-pad/pull/2361