[TEST] Randomize netty worker and connection parameters

Try and push our system to a state where there is only a single worker, trying to expose potential deadlocks when we by mistake execute blocking operations on the worker thread
we could, the default is num_processors * 2, which happens when nextBoolean is false. I wanted to try and be more aggressive when it is enabled. I think this values are good.

regarding the default, I am not sure what a good protection here is. We could protect from someone setting it to 500, or 10 times the number of processors, but I don't think it will be that effective (besides the fact that its a pretty internal and advance setting).