Move the pinned task to front when dismissed split-screen

Split-screen was dismissed after pinning task, but the
pinned task was not moved to front because the split-screen
secondary organized task was moved to top instead.

Bug: 160153401
Test: pin task in split-screen
Change-Id: Ib327203d5a15c86b5bf00e10a537f253a4bc2359

services/core/java/com/android/server/wm/ActivityStackSupervisor.java

@@ -2177,7 +2177,7 @@ public class ActivityStackSupervisor implements RecentTasks.Callbacks {
                 // split-screen in split-screen.
                 mService.getTaskChangeNotificationController()
                         .notifyActivityDismissingDockedStack();
-                taskDisplayArea.onSplitScreenModeDismissed(task.getStack());
+                taskDisplayArea.onSplitScreenModeDismissed((ActivityStack) task);
                 taskDisplayArea.mDisplayContent.ensureActivitiesVisible(null, 0, PRESERVE_WINDOWS,
                         true /* notifyClients */);
             }