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

tests/language/src/NonParameterizedFactoryTest.dart

Index: tests/language/src/NonParameterizedFactoryTest.dart
diff --git a/tests/language/src/NonParameterizedFactoryTest.dart b/tests/language/src/NonParameterizedFactoryTest.dart
index 7a4c99aa728d699366a973d2d4de8d89010552c6..50ae230002b3ecb5fe1ad4ee870fd99af0b8d997 100644
--- a/tests/language/src/NonParameterizedFactoryTest.dart
+++ b/tests/language/src/NonParameterizedFactoryTest.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;
   }
 }