Use launchRootTask to determine parent of stack we getting

Also, have task org createRootTask create task directly vs. getting one
if it already exists.

Bug: 152619437
Test: They pass!
Change-Id: I2aa40ba79ae229eaeacef823ee9c89267d5028d8
diff --git a/services/core/java/com/android/server/wm/TaskOrganizerController.java b/services/core/java/com/android/server/wm/TaskOrganizerController.java
index 872f254..b641e4c 100644
--- a/services/core/java/com/android/server/wm/TaskOrganizerController.java
+++ b/services/core/java/com/android/server/wm/TaskOrganizerController.java
@@ -277,9 +277,9 @@
                     return null;
                 }
 
-                final Task task = display.mTaskContainers.getOrCreateStack(windowingMode,
-                        ACTIVITY_TYPE_UNDEFINED, false /* onTop */, new Intent(),
-                        null /* candidateTask */, true /* createdByOrganizer */);
+                final Task task = display.mTaskContainers.createStack(windowingMode,
+                        ACTIVITY_TYPE_UNDEFINED, false /* onTop */, null /* info */, new Intent(),
+                        true /* createdByOrganizer */);
                 RunningTaskInfo out = task.getTaskInfo();
                 mLastSentTaskInfos.put(task, out);
                 return out;