Fix for issue# 2894085. Removed update to next pointer. It did not seem right to force it to point somewhere between token boundaries, since that could lead the tokenizer to not recognize an end of token.

expat/lib/xmlparse.c

@@ -3723,7 +3723,6 @@ doProlog(XML_Parser parser,
         return XML_ERROR_NO_ELEMENTS;
       default:
         tok = -tok;
-        next = end;
         break;
       }
     }