Remove Expect from core library.

tests/compiler/dart2js/analyze_api_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.
 
 library analyze_api;
 
+import "package:expect/expect.dart";
 import 'dart:uri';
 import 'dart:io';
 import '../../../sdk/lib/_internal/compiler/compiler.dart' as api;
 import '../../../sdk/lib/_internal/compiler/implementation/apiimpl.dart';
 import '../../../sdk/lib/_internal/compiler/implementation/dart2jslib.dart'
     hide Compiler;
 import '../../../sdk/lib/_internal/compiler/implementation/filenames.dart';
 import '../../../sdk/lib/_internal/compiler/implementation/source_file_provider.dart';
 import '../../../sdk/lib/_internal/libraries.dart';
 
@@ skipping 31 matching lines @@
       null,
       handler.diagnosticHandler,
       libraryRoot, libraryRoot,
       <String>['--analyze-only', '--analyze-all',
                '--categories=Client,Server']);
   compiler.librariesToAnalyzeWhenRun = uriList;
   compiler.run(null);
   Expect.isFalse(handler.hasWarnings);
   Expect.isFalse(handler.hasErrors);
 }