OPS-127: Add 'skip_sqs_queue_check' option to delete_old_arrays.rb script.

This allows us to bypass the SQS queue check when terminating arrays.
Useful when we have launched multiple copies of the same taskworker
arrays, and we know that the queues will not be empty when we shut the
machines down.

BUG: OPS-127

Change-Id: Ica85a2832f2c78ff0243e9127d9f33d76f70102b
Merge "OPS-127: Add 'skip_sqs_queue_check' option to delete_old_arrays.rb script." into red_black