Revert "SystemUI: Fix missing top task in recent panel."

See http://review.cyanogenmod.org/#/c/74397/

This reverts commit 0616667d980db1aa32d6dd1956d6fc2e232cf5a3.

Change-Id: I3276ee4f77e3de5d5b758f3bfb09fdc2341ebb5b