Make test message be able to toggle between 'verbose' and 'simple' mode.

In Java, we use the test message peek view to display the stacktrace of the failed cases. sometimes the stacktrace could be very long that contains tens of lines. It would be very helpful if the peek view can accept two set of messages, one is 'verbose' and another is 'simple'. Users can switch between them. #### Some examples of this UX in other IDES: ##### IntelliJ  ##### Eclipse