Fix Swarm to run again, and enable its test

frog/gen.dart

 // Copyright (c) 2011, 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.
 
 /**
  * Top level generator object for writing code and keeping track of
  * dependencies.
  *
  * Should have two compilation models, but only one implemented so far.
  *
@@ skipping 430 matching lines @@
         }
       }
       writer.exitBlock('}');
 
       // Keep const expressions shared across isolates. Note that the frog
       // isolate library needs this because we wrote it's bootstrap and
       // book-keeping directly in Dart. Specifically, that code uses
       // [HashMapImplementation] which internally uses a constant expression.
       for (var global in list) {
         if (global.field == null) {
-          writer.writeln('${global.name} = ${global.exp.code};');
+          writer.writeln('var ${global.name} = ${global.exp.code};');
         }
       }
     }
 
     if (!corejs.useIsolates) {
       if (hasStatics) {
         writer.writeln('var \$globals = {};');
       }
       if (globals.length > 0) {
         writer.writeln('\$static_init();');
@@ skipping 1928 matching lines @@
       result.add(new Value(world.varType, '\$$i', null, /*needsTemp:*/false));
     }
     for (int i = bareCount; i < length; i++) {
       var name = getName(i);
       if (name == null) name = '\$$i';
       result.add(new Value(world.varType, name, null, /*needsTemp:*/false));
     }
     return new Arguments(nodes, result);
   }
 }