Conformance: Add a complience test for Gateway support of multiple targetPorts in an InferencePool

[shmuelk]

Gateway Inference Extension (GIE) 1.0.0 comes with v1 of the InferencePool CRD. One of the changes was to make targetPort an array.

However, there wasn't support for more than one item in that array.

PRs #1653 and #1663 add support for more than item in the targetPorts array.

With that support an addition conformance test is needed to verify that Gateways properly support InferencePool CRs with more than one targetPort item.