Updates dartc to recognize 'default' keyword on interface and updated factory method syntax

tests/language/src/NonParameterizedFactory2Test.dart

Index: tests/language/src/NonParameterizedFactory2Test.dart
diff --git a/tests/language/src/NonParameterizedFactory2Test.dart b/tests/language/src/NonParameterizedFactory2Test.dart
index e896e23bb39c1b94b179b1acc365cffdcc9498a6..b223ae951902e33bbe95af4a4c68fd47bd3a7aa5 100644
--- a/tests/language/src/NonParameterizedFactory2Test.dart
+++ b/tests/language/src/NonParameterizedFactory2Test.dart
@@ -2,17 +2,17 @@
 // 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.
 
-interface Interface<T> factory Factory {
+interface Interface<T> default Factory {
   Interface();
   Interface.withArg(T value);
 }
 
-class Factory {
-  factory Interface<T>() {
+class Factory<T> {
+  factory Interface() {
     return null;
   }
 
-  factory Interface<T>.withArg(value) {
+  factory Interface.withArg(value) {
     return null;
   }
 }