Assert IPs returned in round-robin fashion in the multicluster test

[averevki]

DNS resolution in the nightly pipeline should now work the same as your local dns resolver. Therefore assert for round robin strategy should also work in nightlies

Closes #495

[trepel]

Nice! I would maybe try two Robin rounds but I am probably too suspicious and it is overkill.

    dns_ip1 = dns.resolver.resolve(hostname.hostname)[0].address
    dns_ip2 = dns.resolver.resolve(hostname.hostname)[0].address
    dns_ip3 = dns.resolver.resolve(hostname.hostname)[0].address
    dns_ip4 = dns.resolver.resolve(hostname.hostname)[0].address
    assert dns_ip1 != dns_ip2, "Simple routing strategy should return IPs in a round-robin fashion"
    assert dns_ip1 == dns_ip3
    assert dns_ip2 == dns_ip4