Split dart:builtin into dart:builtin and dart:io.

frog/leg/scanner/scanner_bench.dart

-// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
+// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #library('scanner_bench');
 #import('scannerlib.dart');
 #import('scanner_implementation.dart');
 #source('source_list.dart');
 
 /**
  * A common superclass for scanner benchmarks.
@@ skipping 105 matching lines @@
 
   int score() {
     num geoMean = 1;
     int count = Math.min(scores.length, GEOMEAN_COUNT);
     for (int i = scores.length - count; i < scores.length; i++) {
       geoMean *= scores[i];
     }
     geoMean = Math.pow(geoMean, 1/Math.max(count, 1));
     return geoMean.round().toInt();
   }
-}
+}