Support more checked mode compile time errors in analysis engine.

tests/language/map_literal1_test.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.
 //
 // When type checks are enabled, a type mismatch in a map literal is a compile-time error
 
 main() {
   var m = const
-      <String, String>  /// 01: checked mode compile-time error
+      <String, String>  /// 01: static type warning, checked mode compile-time error
       {"a": 0};
 }