Improve debugging information when worker crash

IE, you can check http://169.254.169.254/latest/meta-data/instance-action to get info that EC2 instance start terminating/stopping/rebooting
(Also, http://169.254.169.254/latest/meta-data/spot/termination-time available only for spot instances)Ideally, show message why it was terminated ("Instance terminated by ASG AZ rebalancing", etc) but it could requires much more work