Call moveHomeStack before moving any stack.

Order matters, otherwise mFocusedStack and mLastStack aren't updated
correctly.

Fixes bug 12478856.

Change-Id: I12e4334678bb3af49d1ff26c4003def3e8d987c2

services/core/java/com/android/server/am/ActivityStack.java

@@ -456,11 +456,11 @@ final class ActivityStack {
 
     final void moveToFront() {
         if (isAttached()) {
-            mStacks.remove(this);
-            mStacks.add(this);
             if (isOnHomeDisplay()) {
                 mStackSupervisor.moveHomeStack(isHomeStack());
             }
+            mStacks.remove(this);
+            mStacks.add(this);
         }
     }