dart2js cps: Compile some loops as 'for' loops.

pkg/compiler/lib/src/tree_ir/tree_ir_tracer.dart

 // Copyright (c) 2014, 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 tree_ir_tracer;
 
 import 'dart:async' show EventSink;
 import '../tracer.dart';
 import 'tree_ir_nodes.dart';
 
@@ skipping 282 matching lines @@
     printStatement(null, "if $condition then $thenTarget else $elseTarget");
   }
 
   visitWhileTrue(WhileTrue node) {
     printStatement(null, "while true do");
   }
 
   visitWhileCondition(WhileCondition node) {
     String bodyTarget = collector.substatements[node.body].name;
     String nextTarget = collector.substatements[node.next].name;
+    String updates = node.updates.map(expr).join(', ');
     printStatement(null, "while ${expr(node.condition)}");
     printStatement(null, "do $bodyTarget");
+    printStatement(null, "updates ($updates)");
     printStatement(null, "then $nextTarget" );
   }
 
   visitTry(Try node) {
     String tryTarget = collector.substatements[node.tryBody].name;
     String catchParams = node.catchParameters.map(names.varName).join(',');
     String catchTarget = collector.substatements[node.catchBody].name;
     printStatement(null, 'try $tryTarget catch($catchParams) $catchTarget');
   }
 
@@ skipping 272 matching lines @@
       String prefix = v.element == null ? 'v' : '${v.element.name}_';
       while (name == null || _usedNames.contains(name)) {
         name = "$prefix${_counter++}";
       }
       _names[v] = name;
       _usedNames.add(name);
     }
     return name;
   }
 }