You can now delete shadown and switchback tests directly from Console using the UI. On any experiment details view, click the Edit button in the header, then delete in the lower right, and then finally confirm the delete action.
When you delete a shadow test, all of the associated shadow runs are deleted as well. However, baseline runs are left in place as those runs are not tied to the experiment. Deleting a switchback test will not affect any of the runs associated with a switchback test, however, the switchback test information will be removed from those runs.
Note that once the experiment and its associated runs or run data has been deleted they cannot be recovered.