899 test for concurrent gpus

[binocarlos]

This does not close #899 (because we still need to add 5 GPUs to the network) but it adds a test for concurrently scheduling GPU jobs to a network of varying latency and we now log when CalculateJobNodeDistanceDelay drops a job so we can catch when GPUs are not being scheduled to because of it

Additional features:

• we now have a multi-node noop stack setup (we only ever had a single node noop stack)
• we can introduce arbitrary network delays on the transports on any node
• this actually gives us a fast (it's noop) stack for testing distributed networks