Ensure we reset reparenting when launching new splits

- Follow up to ag/24812535, there were a few cases where we don't call
  into prepareEnterSplit() but still need to reset the reparenting
  state to prevent trampolines from breaking splitscreen upon entering.

Fixes: 292454704
Test: Launch split from the menu for app that launches a trampoline
Change-Id: Ia0d825192c3ec78991a75f0501e7ece9d75cb4af

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

@@ -718,6 +718,8 @@ public class StageCoordinator implements SplitLayout.SplitLayoutHandler,
         mSplitLayout.setDivideRatio(splitRatio);
         updateWindowBounds(mSplitLayout, wct);
         wct.reorder(mRootTaskInfo.token, true);
+        wct.setReparentLeafTaskIfRelaunch(mRootTaskInfo.token,
+                false /* reparentLeafTaskIfRelaunch */);
         setRootForceTranslucent(false, wct);
 
         // Make sure the launch options will put tasks in the corresponding split roots
@@ -765,6 +767,8 @@ public class StageCoordinator implements SplitLayout.SplitLayoutHandler,
         mSplitLayout.setDivideRatio(splitRatio);
         updateWindowBounds(mSplitLayout, wct);
         wct.reorder(mRootTaskInfo.token, true);
+        wct.setReparentLeafTaskIfRelaunch(mRootTaskInfo.token,
+                false /* reparentLeafTaskIfRelaunch */);
         setRootForceTranslucent(false, wct);
 
         options1 = options1 != null ? options1 : new Bundle();