Move minitest.dart into the expect package.

pkg/dev_compiler/test/codegen/lib/html/crypto_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 'dart:html';
 import 'dart:typed_data';
 
-import 'package:minitest/minitest.dart';
+import 'package:expect/minitest.dart';
 
 main() {
   group('supported', () {
     test('supported', () {
       expect(Crypto.supported, true);
     });
   });
 
   group('functional', () {
     if (Crypto.supported) {
@@ skipping 18 matching lines @@
       test('type mismatch', () {
         var crypto = window.crypto;
         var data = new Float32List(100);
         expect(() {
           crypto.getRandomValues(data);
         }, throws, reason: 'Only typed array views with integer types allowed');
       });
     }
   });
 }