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

tests/compiler/dart2js/mirrors/mirrors_reader_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.
 
 // Test that everything reachable from a [MirrorSystem] can be accessed.
 
 library test.mirrors.reader;
 
 import "dart:mirrors" hide SourceLocation;
 
 import "package:async_helper/async_helper.dart";
 
 import "mirrors_test_helper.dart";
 import "../../../lib/mirrors/mirrors_reader.dart";
-import "package:compiler/src/util/util.dart";
-import "package:compiler/src/mirrors/dart2js_mirrors.dart";
-import "package:compiler/src/mirrors/source_mirrors.dart";
+import "package:compiler/implementation/util/util.dart";
+import "package:compiler/implementation/mirrors/dart2js_mirrors.dart";
+import "package:compiler/implementation/mirrors/source_mirrors.dart";
 
 class SourceMirrorsReader extends MirrorsReader {
   final Dart2JsMirrorSystem mirrorSystem;
 
   SourceMirrorsReader(this.mirrorSystem,
                       {bool verbose: false, bool includeStackTrace: false})
       : super(verbose: verbose, includeStackTrace: includeStackTrace);
 
   evaluate(f()) {
     try {
@@ skipping 104 matching lines @@
 
 main(List<String> arguments) {
   asyncTest(() => analyzeUri(Uri.parse('dart:core')).
       then((MirrorSystem mirrors) {
     MirrorsReader reader = new SourceMirrorsReader(mirrors,
         verbose: arguments.contains('-v'),
         includeStackTrace: arguments.contains('-s'));
     reader.checkMirrorSystem(mirrors);
   }));
 }