Move dart2js from sdk/lib/_internal/compiler to pkg/compiler

tests/compiler/dart2js/message_kind_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 'dart:async';
 import "package:async_helper/async_helper.dart";
-import 'package:compiler/implementation/dart2jslib.dart' show
+import 'package:compiler/src/dart2jslib.dart' show
     DualKind,
     MessageKind;
 
 import 'message_kind_helper.dart';
 
 import 'dart:mirrors';
 
 main(List<String> arguments) {
   ClassMirror cls = reflectClass(MessageKind);
   Map<String, MessageKind> kinds = <String, MessageKind>{};
@@ skipping 30 matching lines @@
   asyncTest(() => Future.forEach(examples, (String name) {
     print("Checking '$name'.");
     Stopwatch sw = new Stopwatch()..start();
     return check(kinds[name], cachedCompiler).then((var compiler) {
       cachedCompiler = compiler;
       sw.stop();
       print("Checked '$name' in ${sw.elapsedMilliseconds}ms.");
     });
   }));
 }