Use specific messages for const constructor with body.

pkg/compiler/lib/src/diagnostics/messages.dart

 // Copyright (c) 2011, 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.
 
 
 /**
  * The messages in this file should meet the following guide lines:
  *
  * 1. The message should be a complete sentence starting with an uppercase
  * letter, and ending with a period.
@@ skipping 126 matching lines @@
   UNDEFINED_STATIC_SETTER_BUT_GETTER,
   CANNOT_RESOLVE_TYPE,
   RETURN_IN_GENERATIVE_CONSTRUCTOR,
   CLASS_NAME_EXPECTED,
   COMPILER_CRASHED,
   COMPLEX_RETURNING_NSM,
   COMPLEX_THROWING_NSM,
   CONSIDER_ANALYZE_ALL,
   CONST_CALLS_NON_CONST,
   CONST_CALLS_NON_CONST_FOR_IMPLICIT,
-  CONST_CONSTRUCTOR_OR_FACTORY_WITH_BODY,
+  CONST_CONSTRUCTOR_WITH_BODY,
   CONST_CONSTRUCTOR_WITH_NONFINAL_FIELDS,
   CONST_CONSTRUCTOR_WITH_NONFINAL_FIELDS_CONSTRUCTOR,
   CONST_CONSTRUCTOR_WITH_NONFINAL_FIELDS_FIELD,
+  CONST_FACTORY,
   CONST_LOOP_VARIABLE,
   CONST_MAP_KEY_OVERRIDES_EQUALS,
   CONST_WITHOUT_INITIALIZER,
   CONSTRUCTOR_CALL_EXPECTED,
   CONSTRUCTOR_IS_NOT_CONST,
   CONSTRUCTOR_WITH_RETURN_TYPE,
   CYCLIC_CLASS_HIERARCHY,
   CYCLIC_COMPILE_TIME_CONSTANTS,
   CYCLIC_REDIRECTING_FACTORY,
   CYCLIC_TYPE_VARIABLE,
@@ skipping 3462 matching lines @@
   static String convertToString(value) {
     if (value is ErrorToken) {
       // Shouldn't happen.
       return value.assertionMessage;
     } else if (value is Token) {
       value = value.value;
     }
     return '$value';
   }
 }