overview: Avoid repositioning windows while returning to desktop

When returning to the desktop from overview we always show the
workspaceDisplay, given that is which have the windows clones to allow
animations.
The problem becomes when previous that we were at some other
page, like Search or AppDisplay. The problem is that when showing the
workspaceDisplay the windows are repositioned. That's wanted except
when returning from overview, since that causes unwanted animations
of the windows.
To avoid that just not reposition the windows if leaving the overview.

js/ui/workspace.js

@@ -1258,6 +1258,12 @@ const Workspace = new Lang.Class({
             return;
         }
 
+        // We will reposition windows when enter again overview anyway.
+        // In this way we avoid unwanted animations of windows repositioning while
+        // animating overview
+        if (this.leavingOverview)
+            return;
+
         let initialPositioning = flags & WindowPositionFlags.INITIAL;
         let animate = flags & WindowPositionFlags.ANIMATE;