cleanup patch generation to preseve comments and remove @patch

test/generated_sdk/lib/internal/symbol.dart

 // Copyright (c) 2013, 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.
 
 part of dart._internal;
 
 /**
  * Implementation of [core.Symbol].  This class uses the same name as
  * a core class so a user can't tell the difference.
  *
@@ skipping 80 matching lines @@
    * RegExp that validates a non-empty symbol.
    *
    * Private symbols are accepted.
    *
    * The empty symbol is handled before this regexp is used, and is not
    * accepted.
    */
   static final RegExp symbolPattern = new RegExp(
       '^(?:$operatorRE\$|$identifierRE(?:=?\$|[.](?!\$)))+?\$');
 
-  @patch
   const Symbol(String name)
       : this._name = name;
 
   /**
    * Platform-private method used by the mirror system to create
    * otherwise invalid names.
    */
   const Symbol.unvalidated(this._name);
 
   // This is called by dart2js.
@@ skipping 26 matching lines @@
 
   /**
    * Checks whether name is a valid symbol name.
    *
    * This test allows both private and non-private symbols.
    */
   static bool isValidSymbol(String name) {
     return (name.isEmpty || symbolPattern.hasMatch(name));
   }
 }