Enhance `pokeServer` in helper utilities

[tssurya]

See https://github.com/kubernetes-sigs/network-policy-api/pull/99/commits/63394cc816c1d3f78be860a1faa100a6efd4ca42#r1200872040 for details.

• [ ] See if we can improve the parser to be more accurate on what an error means
• [ ] See if we need to retry the connection errors similar to how its done in netpol v1 tests

/area conformance

[tssurya]

/good-first-issue

[k8s-ci-robot]

@tssurya: This request has been marked as suitable for new contributors.

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In response to [this](https://github.com/kubernetes-sigs/network-policy-api/issues/108): >/good-first-issue Instructions for interacting with me using PR comments are available [here](https://git.k8s.io/community/contributors/guide/pull-requests.md). If you have questions or suggestions related to my behavior, please file an issue against the [kubernetes/test-infra](https://github.com/kubernetes/test-infra/issues/new?title=Prow%20issue:) repository.

[Shin-John]

Can I still assign this to myself? I see that there has been a merged mention.

[flavio-fernandes]

Here is the corrected version of your text:

A humble side note I would like to have along with this issue, which I could have used while encountering a problem during the conformance test:

=== RUN   TestNetworkPolicyV2Conformance/AdminNetworkPolicyEgressSCTP/Should_support_an_'allow-egress'_policy_for_SCTP_protocol;_ensure_rule_ordering_is_respected
    admin-network-policy-core-egress-sctp-rules.go:62: FAILED Command was [/agnhost connect --timeout=3s --protocol=sctp 10.192.0.3:9003]
    admin-network-policy-core-egress-sctp-rules.go:62: Expected connection to succeed from network-policy-conformance-ravenclaw/luna-lovegood-0 to 10.192.0.3, but instead it miserably failed. stderr: OTHER: cannot allocate memory

If you see OTHER: cannot allocate memory while running the test, try increasing the amount of memory on the nodes running the test pods. In my particular test setup, a 16GB VM for 3 nodes was not enough. YMMV (your mileage may vary).