Clean up NPEs in AbsSwipeUpHandler

AbsSwipeUphandler has many potential and common NPEs. Added more null checks to AbsSwipeUpHandler

Flag: N/A
Fixes: 295905702
Fixes: 309535060
Test: StartLauncherViaGestureTests, quick switched and launched app from recents
Change-Id: I11f62eac423ae3c5792ce97ca49963f1e005b289
2 files changed