The test "should enforce egress policy allowing traffic to a server in a
different namespace based on PodSelector and NamespaceSelector
[Feature:NetworkPolicy]" is flaky because it doesn't wait for the server
Pod to be ready before testing traffic via its service, then even the
NetworkPolicy allows it, the SYN packets will be rejected by iptables
because the service has no endpoints at that moment.
This PR fixes it by making it wait for Pods to be ready like other
tests.
92759ea642