Move minitest.dart into the expect package.

pkg/dev_compiler/test/codegen/lib/html/element_types_constructors3_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);
     });
   }
@@ skipping 12 matching lines @@
     check('ins', () => new Element.tag('ins') is ModElement);
     check('object', () => new ObjectElement() is ObjectElement,
         ObjectElement.supported);
     check('ol', () => new OListElement() is OListElement);
     check('optgroup', () => new OptGroupElement() is OptGroupElement);
     check('option', () => new OptionElement() is OptionElement);
     check('output',
         () => new OutputElement() is OutputElement, OutputElement.supported);
   });
 }