Modified unittest to use new argument syntax.

tests/html/window_mangling_test.dart

Index: tests/html/window_mangling_test.dart
===================================================================
--- tests/html/window_mangling_test.dart	(revision 14156)
+++ tests/html/window_mangling_test.dart	(working copy)
@@ -20,16 +20,16 @@
   test('windowMethod', () {
       final message = navigator;
       final x = win.navigator;
-      Expect.notEquals(message, x);
+      expect(x, isNot(equals(message)));
     });
 
   test('windowEquals', () {
-      Expect.isFalse($eq(win, win));
-      Expect.isTrue(win == win);
+      expect($eq(win, win), isFalse);
+      expect(win == win, isTrue);
     });
 
   test('windowEquals', () {
-      Expect.isFalse($eq$(win, win));
-      Expect.isTrue(win == win);
+      expect($eq$(win, win), isFalse);
+      expect(win == win, isTrue);
     });
 }