Fixing timeout caused by non executed animation

The problem became apparent after a springboard activity
called another activity and a moveTaskToFront got requested.

This issue is similar to ag/1647538 where an
ExecuteAppTransision was missing and a timeout occured.

Bug: 33307856
Test: Start PlayStore on ARC++ several times to see that
it shows up immediately and not after a considerable delay.

Change-Id: I25b63bd65385a4ad45bbb1803ae92fb48fe5fe4d
(cherry picked from commit 06f78e83d1010fa5420c7fe88a0b27eb3651bdc3)
diff --git a/services/core/java/com/android/server/am/ActivityStackSupervisor.java b/services/core/java/com/android/server/am/ActivityStackSupervisor.java
index db9e0f6..fe261f1 100644
--- a/services/core/java/com/android/server/am/ActivityStackSupervisor.java
+++ b/services/core/java/com/android/server/am/ActivityStackSupervisor.java
@@ -1844,6 +1844,9 @@
         final ActivityRecord r = mFocusedStack.topRunningActivityLocked();
         if (r == null || r.state != RESUMED) {
             mFocusedStack.resumeTopActivityUncheckedLocked(null, null);
+        } else if (r.state == RESUMED) {
+            // Kick off any lingering app transitions form the MoveTaskToFront operation.
+            mFocusedStack.executeAppTransition(targetOptions);
         }
         return false;
     }