Revert "Connect split-screen things to systemui divider"

Revert "SystemUI Split via TaskOrganizer"

Revert "Update CTS tests for tile-based split-screen"

Revert submission 9964969-sysui_split_screen

Reason for revert:
- Random SysUI crash (ag/10335781)
- Breaks IME tests with new_insets set to 2
- Crashes SysUI in split screen with new_insets set to 2.

Reverted Changes:
I103f68030: SystemUI Split via TaskOrganizer
If6740b7ee: Connect split-screen things to systemui divider
I44f497e7d: Update CTS tests for tile-based split-screen

Exempt-From-Owner-Approval: Revert
Change-Id: I9d5d7f0447fdfaf73f4e0a6450a2107bceec39cb