Add more tests and fix the parser to deal with generic superclasses for mixin applications.

tests/language/mixin_type_parameters_super_extends_test.dart

Index: tests/language/mixin_type_parameters_super_extends_test.dart
diff --git a/tests/language/mixin_type_parameters_super_test.dart b/tests/language/mixin_type_parameters_super_extends_test.dart
similarity index 95%
copy from tests/language/mixin_type_parameters_super_test.dart
copy to tests/language/mixin_type_parameters_super_extends_test.dart
index 5c4b66086fb760e851530ac50b430c5793980907..d05fd7a2c428dbc1f9fe703579a9b423c229fa0f 100644
--- a/tests/language/mixin_type_parameters_super_test.dart
+++ b/tests/language/mixin_type_parameters_super_extends_test.dart
@@ -38,10 +38,10 @@ class S<T> {
 class M {
 }
 
-typedef C0<T> = S with M;
-typedef C1<T> = S<T> with M;
-typedef C2<T> = S<int> with M;
-typedef C3 = S<String> with M;
+class C0<T> extends S with M { }
+class C1<T> extends S<T> with M { }
+class C2<T> extends S<int> with M { }
+class C3 extends S<String> with M { }
 
 main() {
   var c0 = new C0();