Move minitest.dart into the expect package.

pkg/dev_compiler/test/codegen/lib/html/element_types_constructors6_test.dart

 // Copyright (c) 2012, 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 'package:minitest/minitest.dart';
+import 'package:expect/minitest.dart';
 
 main() {
   check(String name, bool fn(), [bool supported = true]) {
     test(name, () {
       var expectation = supported ? returnsNormally : throws;
       expect(() {
         expect(fn(), isTrue);
       }, expectation);
     });
   }
 
   group('ul', () {
     check('ul', () => new UListElement() is UListElement);
 
     test('accepts li', () {
       var ul = new UListElement();
       var li = new LIElement();
       ul.append(li);
     });
   });
   group('constructors', () {
     check('video', () => new VideoElement() is VideoElement);
     check('unknown', () => new Element.tag('someunknown') is UnknownElement);
   });
 }