Implement new mixin application syntax

tests/language/mixin_black_listed_test.dart

Index: tests/language/mixin_black_listed_test.dart
===================================================================
--- tests/language/mixin_black_listed_test.dart	(revision 28595)
+++ tests/language/mixin_black_listed_test.dart	(working copy)
@@ -25,17 +25,17 @@
 , double /// 04: compile-time error
 , D {}
 
-typedef C2 = Object with num; /// 05: compile-time error
+class C2 = Object with num; /// 05: compile-time error
 
-typedef D2 = Object with C
+class D2 = Object with C
 , bool /// 06: compile-time error
 ;
 
-typedef E2 = Object with
+class E2 = Object with
 String, /// 07: compile-time error
 C;
 
-typedef F2 = Object with C,
+class F2 = Object with C,
 dynamic, /// 08: compile-time error
 D;