Command /save-off does not turn off autosaving on server shutdown

The bug

While auto-save is turned off (/save-off command), the server still saves the inventories and position of players and ender chests, as well as the world and chest inventories. When the server is stopped, player positions and the world are saved.

How to reproduce

1. Start your SMP server
2. Run the /save-off command
3. Move around, edit the world, place items in your chests and ender chests
4. Stop the server with the /stop command
5. Reboot the server normally
   → Your position and items in your inventory, as well as your changes to the world, remain