Move minitest.dart into the expect package.

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

 import 'dart:html';
 import 'dart:html_common';
 
-import 'package:minitest/minitest.dart';
+import 'package:expect/minitest.dart';
 
 main() {
   var t1 = new Text('T1'),
       t2 = new Text('T2'),
       t3 = new Text('T3'),
       t4 = new Text('T4');
 
   var d1 = new DivElement(),
       d2 = new DivElement(),
       d3 = new DivElement();
@@ skipping 83 matching lines @@
     expect(elementList.removeLast(), br);
     elementList.add(br);
     expect(elementList.remove(br), isTrue);
     var br2 = new BRElement();
     elementList.add(br);
     expect(elementList.remove(br2), isFalse);
     expect(elementList[0], br);
     expect(() => elementList[1], throwsRangeError);
  });
 }