[4.2] Session:  Call Artisan dump-autoload after session:table

As `dump-autoload` is a post-requirement to `session:table` (https://github.com/laravel/docs/blob/1a55def4d49605ea2953796b7fef1792bc106a18/session.md#database-sessions), it can be added after `session:table` command.

Also closes https://github.com/laravel/framework/pull/4657