Update mirror tests for removed API.

tests/lib/mirrors/generics_substitution_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.
 
 library test.generics_substitution;
 
 import 'dart:mirrors';
 import 'package:expect/expect.dart';
 
 class SuperGeneric<R, S> {
@@ skipping 11 matching lines @@
   ClassMirror superGenericDecl = reflectClass(SuperGeneric);
   ClassMirror superOfTAndInt = genericDecl.superclass;
   ClassMirror superOfStringAndInt = genericOfString.superclass;
 
   Expect.isTrue(genericDecl.isOriginalDeclaration);
   Expect.isFalse(genericOfString.isOriginalDeclaration);
   Expect.isTrue(superGenericDecl.isOriginalDeclaration);
   Expect.isFalse(superOfTAndInt.isOriginalDeclaration);
   Expect.isFalse(superOfStringAndInt.isOriginalDeclaration);
 
-  Symbol r(ClassMirror cm) => cm.variables[#r].type.simpleName;
-  Symbol s(ClassMirror cm) => cm.methods[#s].parameters[0].type.simpleName;
-  Symbol t(ClassMirror cm) => cm.methods[#t].returnType.simpleName;
+  Symbol r(ClassMirror cm) =>
+      (cm.declarations[#r] as VariableMirror).type.simpleName;
+  Symbol s(ClassMirror cm) =>
+      (cm.declarations[#s] as MethodMirror).parameters[0].type.simpleName;
+  Symbol t(ClassMirror cm) =>
+      (cm.declarations[#t] as MethodMirror).returnType.simpleName;
 
   Expect.equals(#T, r(genericDecl.superclass)); /// 01: ok
   Expect.equals(#int, s(genericDecl.superclass));
   Expect.equals(#T, t(genericDecl));
 
   Expect.equals(#String, r(genericOfString.superclass)); /// 01: ok
   Expect.equals(#int, s(genericOfString.superclass));
   Expect.equals(#String, t(genericOfString));
 
   Expect.equals(#R, r(superGenericDecl)); /// 01: ok
   Expect.equals(#S, s(superGenericDecl));
 
   Expect.equals(#T, r(superOfTAndInt)); /// 01: ok
   Expect.equals(#int, s(superOfTAndInt));
 
   Expect.equals(#String, r(superOfStringAndInt)); /// 01: ok
   Expect.equals(#int, s(superOfStringAndInt));
 }