Don't show app menu icon split option or overview
action split option when current taskView is already in
split or there are not at least 2 tasks with which to
invoke split
Fixes: 197245395
Test: Tested with small and large screen,
dismissing tasks in overview, with and without
GroupedTaskView as main running task
Change-Id: I90cc3c39e4d94662cb87314a210d45d145b6e026