The NetworkPolicy tests work by trying to connect to a service by its
name, which means that for the tests that involved creating egress
policies, it had to always create an extra rule allowing egress for
DNS, but this assumed that DNS was running on UDP port 53. If it was
running somewhere else (eg if you changed the CoreDNS pods to use port
5353 to avoid needing to give them the NET_BIND_SERVICE capability)
then the NetworkPolicy tests would fail.
Fix this by making the tests connect to their services by IP rather
than by name, and removing all the DNS special-case rules. There are
other tests that ensure that Service DNS works.
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