Fix seeing "punch-hole" split-tasks when switching tasks from recents

If split-screen task is on the overview, since it has controlled by
recents remote animation, we should not dismiss split-screen, in case
when taping the side task on the overview to perform launch fullscreen
task transition and animating split-screen in parallel but the
transition leash can't control the split-tasks because of the
split-screen dismissal.

Fix: 228965939
Test: manual as issue steps:
  1) launch several fullscreen apps
  2) enter split-screen mode from the overview
  3) swipe the split-screen task to overview again
  4) tap the side task to let it going to foreground
  5) verify the split-screen task should keep visible and
     animating as well.
Change-Id: Ie5463cfd3a062d1166a52951ff55b77175ee42ed

libs/WindowManager/Shell/src/com/android/wm/shell/splitscreen/StageCoordinator.java

@@ -1444,8 +1444,9 @@ public class StageCoordinator implements SplitLayout.SplitLayoutHandler,
                     // Enter overview panel, so start recent transition.
                     mSplitTransitions.setRecentTransition(transition,
                             request.getRemoteTransition());
-                } else {
-                    // Occluded by the other fullscreen task, so dismiss both.
+                } else if (mSplitTransitions.mPendingRecent == null) {
+                    // If split-task is not controlled by recents animation
+                    // and occluded by the other fullscreen task, dismiss both.
                     prepareExitSplitScreen(STAGE_TYPE_UNDEFINED, out);
                     mSplitTransitions.setDismissTransition(transition,
                             STAGE_TYPE_UNDEFINED, EXIT_REASON_UNKNOWN);