Example request: Multiselect/dropdown list/combobox

It would be nice to have an example showing how to write tests for something like: https://react-spectrum.adobe.com/react-spectrum/ComboBox.html

Since this UI component is something that is difficult to implement accessibly and including all the intricate keyboard behaviors correctly, it is a good candidate for an example test. The test can show all the keyboard and mouse behaviors. We might also want to integrate axe accessibility testing with this test ([related issue](https://github.com/cloudfour/test-mule/issues/39))