Don't send more ticks than necessary

[mkorbel1]

There are some scenarios where ROHD Cosim will send multiple ticks to the SV simulator back-to-back without any additional value added (e.g. I think if there are no events in a given time). This is a waste of processing, socket communication, and overall simulation time. If it happens frequently it could potentially impact overall simulation duration.

We should avoid sending ticks that aren't necessary.