Move minitest.dart into the expect package.

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

 // Copyright (c) 2011, 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:collection';
 import 'dart:html';
 
-import 'package:minitest/minitest.dart';
+import 'package:expect/minitest.dart';
 
 Element makeElement() => new Element.tag('div');
 
 Element makeElementWithClasses() =>
     new Element.html('<div class="foo bar baz"></div>');
 
 CssClassSet makeClassSet() => makeElementWithClasses().classes;
 
 Element makeListElement() =>
     new Element.html('<ul class="foo bar baz">'
@@ skipping 365 matching lines @@
     expect(view(elements.classes), '[quux, qux]');
     expect(view(elements), '[[quux, qux], [], [], [qux]]');
   });
 
   test('listContainsAll', () {
     var elements = listElementSetup();
     expect(elements.classes.containsAll(['qux', 'meta', 'mornin']), isFalse);
     expect(elements.classes.containsAll(['qux', 'lassy', 'classy']), isTrue);
   });
 }