Introduce .isMalformed

tests/compiler/dart2js/patch_test.dart

 // Copyright (c) 2012, 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:async';
 import 'package:expect/expect.dart';
 import 'package:async_helper/async_helper.dart';
 import 'package:compiler/src/compiler.dart';
 import 'package:compiler/src/diagnostics/messages.dart' show
     MessageKind;
@@ skipping 954 matching lines @@
   ClassElement clsA = compiler.coreLibrary.find("A");
   ClassElement clsB = compiler.coreLibrary.find("B");
 
   ConstructorElement forward = clsA.lookupConstructor("forward");
   ConstructorElement target = forward.effectiveTarget;
   Expect.isTrue(target.isPatch);
   Expect.equals("patchTarget", target.name);
 
   ConstructorElement forwardTwo = clsA.lookupConstructor("forwardTwo");
   target = forwardTwo.effectiveTarget;
-  Expect.isFalse(forwardTwo.isErroneous);
+  Expect.isFalse(forwardTwo.isMalformed);
   Expect.isFalse(target.isPatch);
   Expect.equals("originTarget", target.name);
 }
 
 Future testTypecheckPatchedMembers() async {
   String originText = "external void method();";
   String patchText = """
                      @patch void method() {
                        String s = 0;
                      }
@@ skipping 40 matching lines @@
     await testPatchNonFunction();
 
     await testPatchAndSelector();
 
     await testEffectiveTarget();
 
     await testAnalyzeAllInjectedMembers();
     await testTypecheckPatchedMembers();
   });
 }