Make error message deterministic

pkg/analyzer/lib/src/generated/error_verifier.dart

 // Copyright (c) 2014, 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 analyzer.src.generated.error_verifier;
 
 import 'dart:collection';
 import "dart:math" as math;
 
 import 'package:analyzer/dart/ast/ast.dart';
@@ skipping 4624 matching lines @@
       }
       if (enclosingElement != null) {
         newStrMember =
             "$prefix'${enclosingElement.displayName}.${missingOverridesArray[i].displayName}'";
       } else {
         newStrMember = "$prefix'${missingOverridesArray[i].displayName}'";
       }
       stringMembersArrayListSet.add(newStrMember);
     }
     List<String> stringMembersArray = new List.from(stringMembersArrayListSet);
+    stringMembersArray.sort();
     AnalysisErrorWithProperties analysisError;
     if (stringMembersArray.length == 1) {
       analysisError = _errorReporter.newErrorWithProperties(
           StaticWarningCode.NON_ABSTRACT_CLASS_INHERITS_ABSTRACT_MEMBER_ONE,
           classNameNode,
           [stringMembersArray[0]]);
     } else if (stringMembersArray.length == 2) {
       analysisError = _errorReporter.newErrorWithProperties(
           StaticWarningCode.NON_ABSTRACT_CLASS_INHERITS_ABSTRACT_MEMBER_TWO,
           classNameNode,
@@ skipping 1548 matching lines @@
     toCheck.add(type.element);
     // type arguments
     if (type is InterfaceType) {
       InterfaceType interfaceType = type;
       for (DartType typeArgument in interfaceType.typeArguments) {
         _addTypeToCheck(typeArgument);
       }
     }
   }
 }