Use UTF-8 when serving web pages for analysis server debug.

pkg/analysis_server/lib/src/status/ast_writer.dart

 // Copyright (c) 2015, 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 analysis_server.src.status.ast_writer;
 
-import 'package:analysis_server/src/status/utilities.dart';
+import 'dart:convert';
+
 import 'package:analyzer/src/generated/ast.dart';
 
 /**
  * A visitor that will produce an HTML representation of an AST structure.
  */
 class AstWriter extends UnifyingAstVisitor {
   /**
    * The buffer on which the HTML is to be written.
    */
   final StringBuffer buffer;
@@ skipping 150 matching lines @@
     }
   }
 
   /**
    * Write the [value] of the property with the given [name].
    */
   void _writeProperty(String name, Object value) {
     if (value != null) {
       _indent(2);
       buffer.write('$name = ');
-      buffer.write(encodeHtml(value.toString()));
+      buffer.write(HTML_ESCAPE.convert(value.toString()));
       buffer.write('<br>');
     }
   }
 }