Move minitest.dart into the expect package.

pkg/dev_compiler/test/codegen/lib/html/element_add_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';
 
 import 'util.dart';
 
 main() {
   var isSpanElement = predicate((x) => x is SpanElement, 'is a SpanElemt');
   var isDivElement = predicate((x) => x is DivElement, 'is a DivElement');
   var isText = predicate((x) => x is Text, 'is a Text');
 
   void expectNoSuchMethod(void fn()) =>
     expect(fn, throwsNoSuchMethodError);
@@ skipping 241 matching lines @@
       var child = new DivElement();
       parent.children.add(child);
 
       parent.insertAdjacentText('beforeend', 'test');
 
       expect(parent.nodes.length, 2);
       expect(parent.nodes[1], isText);
     });
   });
 }