test: verify occurrence of redirections just in case

[supercaracal]

No description provided.

[supercaracal]

The following case is flaky in JRuby:

  4) Error:
RedisClient::TestCluster::ScaleReadRandom#test_pubsub_with_wrong_command:
RedisClient::Cluster::ErrorCollection: Errors occurred on any node: 172.18.0.2:6379: Waited 6.1 seconds
    lib/redis_client/cluster/node.rb:267:in `call_multiple_nodes!'
    lib/redis_client/cluster/node.rb:135:in `call_primaries'
    lib/redis_client/cluster/router.rb:240:in `send_wait_command'
    lib/redis_client/cluster/router.rb:41:in `send_command'
    lib/redis_client/cluster.rb:56:in `blocking_call'
    test/redis_client/test_cluster.rb:893:in `block in wait_for_replication'
    test/testing_helper.rb:33:in `swap_timeout'
    test/redis_client/test_cluster.rb:892:in `wait_for_replication'
    test/redis_client/test_cluster.rb:20:in `teardown'