private FindCoordinatorResponse groupCoordinatorResponse(Node node, Errors error) {
        return FindCoordinatorResponse.prepareResponse(error, groupId, node);
    }
Verifies that subscription change updates SubscriptionState correctly even after JoinGroup failures
that don't re-invoke onJoinPrepare.
clients/src/test/java/org/apache/kafka/clients/consumer/internals/ConsumerCoordinatorTest.java