Fix the help message printed by standalone dart

runtime/bin/main.cc

 // Copyright (c) 2012, 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.
 
 #include <stdlib.h>
 #include <string.h>
 #include <stdio.h>
 
 #include "include/dart_api.h"
 #include "include/dart_debugger_api.h"
@@ skipping 534 matching lines @@
 "\n"
 "--debug[:<port number>]\n"
 "  enables debugging and listens on specified port for debugger connections\n"
 "  (default port number is 5858)\n"
 "\n"
 "--break_at=<location>\n"
 "  sets a breakpoint at specified location where <location> is one of :\n"
 "  url:<line_num> e.g. test.dart:10\n"
 "  [<class_name>.]<function_name> e.g. B.foo\n"
 "\n"
-"--use-script-snapshot=<file_name>\n"
-"  executes Dart script present in the specified snapshot file\n"
-"\n"
 "--generate-script-snapshot=<file_name>\n"
 "  loads Dart script and generates a snapshot in the specified file\n"
 "\n"
-"--print-source\n"
+"--print-script\n"
 "  generates Dart source code back and prints it after parsing a Dart script\n"
 "\n"
 "--stats[:<port number>]\n"
 "  enables VM stats service and listens on specified port for HTTP requests\n"
 "  (default port number is dynamically assigned)\n"
 "\n"
 "--stats-root=<path>\n"
 "  where to find static files used by the vmstats application\n"
 "  (used during vmstats plug-in development)\n"
 "\n"
@@ skipping 268 matching lines @@
   Dart_ShutdownIsolate();
   // Terminate process exit-code handler.
   Process::TerminateExitCodeHandler();
   // Free copied argument strings if converted.
   if (argv_converted) {
     for (int i = 0; i < argc; i++) free(argv[i]);
   }
 
   return Process::GlobalExitCode();
 }