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

tests/compiler/dart2js/deferred_emit_type_checks_test.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.
 
 // Test that the additional runtime type support is output to the right
 // Files when using deferred loading.
 
 import 'package:expect/expect.dart';
 import "package:async_helper/async_helper.dart";
 import 'memory_source_file_helper.dart';
 import "dart:async";
 
-import 'package:compiler/implementation/dart2jslib.dart'
+import 'package:compiler/src/dart2jslib.dart'
        as dart2js;
 
 class MemoryOutputSink<T> extends EventSink<T> {
   List<T> mem = new List<T>();
   void add(T event) {
     mem.add(event);
   }
   void addError(T event, [StackTrace stackTrace]) {}
   void close() {}
 }
@@ skipping 48 matching lines @@
 }
 """, "lib.dart": """
 class A<T> {}
 
 A<A> instance = new A<A>();
 
 bool f (Object o) {
   return o is A<A>;
 }
 """,};