cassandra-stress: not all contact point are passed down to driver

Seem like c-s is randomly selecting a node from the nodes passed down to it in the command line, and use that node as contact point to the driver.

When using c-s together with other management operations (for example expending/shrinking the cluster), we can get into situation some of the nodes mentioned in the command line aren't reachable/available, and c-s instead of applying the best practice of having multiple contact points, pass down only one that can be unavailable and fail completely without trying any of the other nodes mentioned in the command line

we just fixed that in our fork of cassandra-stress:

https://github.com/scylladb/scylla-tools-java/pull/314