Automatic merge from submit-queue
Add e2e network policy tests.
**What this PR does / why we need it**:
Add set of e2e tests for Network Policy. This has succesfully run againast a deployment using Calico as the network policy provider.
Specifically, adds a new e2e test file (/test/e2e/network_policy.go) which tests TCP connectivity between pods with isolation.
See #25638 for PR that added NetworkPolicy resource.
This PR is a replacement for #27447 .