Re-triage mirror test failures on the analyzer.

tests/lib/mirrors/method_mirror_properties_test.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // 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.
 
 import "dart:mirrors";
 
 import "package:expect/expect.dart";
 
 doNothing42() {}
 
 int _x = 5;
 int get topGetter => _x;
 void set topSetter(x) { _x = x; }
 
-class AbstractC {
+abstract class AbstractC {
 
   AbstractC();
 
   void bar();
   get priv;
   set priv(value);
 }
 
-class C extends AbstractC {
+abstract class C extends AbstractC {
 
   static foo() {}
 
   C();
   C.other();
   C.other2() : this.other();
 
   var _priv;
   get priv => _priv;
   set priv(value) => _priv = value;
@@ skipping 34 matching lines @@
   classMirror = reflectClass(AbstractC);
   checkKinds(classMirror.constructors[#AbstractC],
       [false, false, false, false, true]);
   checkKinds(classMirror.members[#bar],
       [false, true, false, false, false]);
   checkKinds(classMirror.members[#priv],
       [false, true, true, false, false]);
   checkKinds(classMirror.members[const Symbol("priv=")],
       [false, true, false, true, false]);
 }