Modified unittest to use new argument syntax.

tests/html/domparser_test.dart

Index: tests/html/domparser_test.dart
===================================================================
--- tests/html/domparser_test.dart	(revision 14156)
+++ tests/html/domparser_test.dart	(working copy)
@@ -7,9 +7,11 @@
 
   useHtmlConfiguration();
 
+  var isDOMParser = predicate((x) => x is DOMParser, 'is a DOMParser');
+
   test('constructorTest', () {
       var ctx = new DOMParser();
-      Expect.isTrue(ctx != null);
-      Expect.isTrue(ctx is DOMParser);
+      expect(ctx, isNotNull);
+      expect(ctx, isDOMParser);
   });
 }