Fixes first jump of dividerview when invoking splitscreen

The divider's position at the beginning is set to empty rect because
splitscreen is not ready yet so it sets the previous position that is
empty rect. In this case, the divider is positioned when splitscreen is
not ready yet but divider becomes visible so it shows this jump. If
the divider was set to splitscreen ignoring visibility then the divider
will be positioned correctly.

Change-Id: Ic959a4ade89d07ccfeeb8179e2f08e34d31860d6
Fixes: 79262454
Test: reboot, invoke splitscreen via overview