The new "streams" protocol behaves slightly different to the "classic"
protocol, and thus we need to update the test to avoid race conditions.
In particular, the first call to `poll()` won't "block" and return after
task assignment completed if we need to create internal topics, but
returns early without a task assignment, and only a consecutive
rebalance will assign tasks.
This implies, that KafkaStreams transits to RUNNING state even if the
group is still in NOT_READY state broker side, but this NOT_READY state
is not reflected in the client side state machine.
Disabling the combination of "complex-topology + streams" for now,
until this difference in behavior of the client state machine is fixed.
Reviewers: Lucas Brutschy <lbrutschy@confluent.io>
