Make --always-opt also optimize toplevel code.

test/mjsunit/debug-compile-event-newfunction.js

 // Copyright 2010 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 43 matching lines @@
   } catch (e) {
     exception = e
   }
 };
 
 
 // Add the debug event listener.
 Debug.setListener(listener);
 
 // Create a function from its body text. It will lead to an eval.
-new Function('arg1', 'return arg1 + 1;');
+var f = new Function('arg1', 'return arg1 + 1;');
+// TODO(titzer): Assignment only needed because source positions are borked.
 
 assertNull(exception, "exception in listener");
 
 Debug.setListener(null);