Modified unittest to use new argument syntax.

pkg/unittest/test/matchers_test.dart

Index: pkg/unittest/test/matchers_test.dart
===================================================================
--- pkg/unittest/test/matchers_test.dart	(revision 14156)
+++ pkg/unittest/test/matchers_test.dart	(working copy)
@@ -170,8 +170,7 @@
           throwsUnsupportedError);
       shouldFail(() { throw new Exception(); },
           throwsUnsupportedError,
-        "Expected: throws an exception which matches "
-            "UnsupportedError "
+        "Expected: throws an exception which matches UnsupportedError "
         "but:  exception <Exception> does not match "
             "UnsupportedError.");
     });
@@ -527,11 +526,9 @@
 
   group('Predicate Matchers', () {
     test('isInstanceOf', () {
-      shouldFail(0, predicate((x) => x is String,
-                              description: "an instance of String"),
+      shouldFail(0, predicate((x) => x is String, "an instance of String"),
           "Expected: an instance of String but: was <0>.");
-      shouldPass('cow', predicate((x) => x is String,
-                                  description: "an instance of String"));
+      shouldPass('cow', predicate((x) => x is String, "an instance of String"));
     });
   });