Move dart2jslib parts into separate libraries.

tests/compiler/dart2js/list_tracer_test.dart

 // Copyright (c) 2013, 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.
 
 import 'package:expect/expect.dart';
 import "package:async_helper/async_helper.dart";
 import 'package:compiler/src/types/types.dart'
     show ContainerTypeMask, TypeMask;
 
 import 'compiler_helper.dart';
-import 'parser_helper.dart';
 import 'type_mask_test_helper.dart';
 
 String generateTest(String listAllocation) {
   return """
 int anInt = 42;
 double aDouble = 42.5;
 
 class A {
   final field;
   var nonFinalField;
@@ skipping 213 matching lines @@
     checkType('listPassedAsNamedParameter', typesTask.numType);
     checkType('listStoredInList', typesTask.uint31Type);
     checkType('listStoredInListButEscapes', typesTask.dynamicType);
 
     if (!allocation.contains('filled')) {
       checkType('listUnset', new TypeMask.nonNullEmpty());
       checkType('listOnlySetWithConstraint', new TypeMask.nonNullEmpty());
     }
   }));
 }