Disable Masquerading for Cilium ENI mode

[rifelpet]

This reverts #14694. Enabling masquerading was needed when upgrading from cilium 1.10 to 1.11, but it wasn't understood why this was needed, and it didnt make sense.

Since the cilium 1.14 upgrade, cilium-eni grid tests have started failing (example). Reproing this locally I've confirmed that the tests are failing because pods with hostNetwork=false are timing out reaching pods on other nodes, including the apiserver:

Failed to watch *v1.Node: failed to list *v1.Node: Get "[https://100.64.0.1:443/api/v1/nodes?limit=500&resourceVersion=0](https://100.64.0.1/api/v1/nodes?limit=500&resourceVersion=0)": dial tcp 100.64.0.1:443: i/o timeout

Notice that all failing tests in the grid jobs involve network communication with other pods or kube-apiserver.

Troubleshooting confirmed that the request is leaving the source instance on the instance's default ENI rather than the pod IP's ENI (this is by design of cilium masquerading) and the traffic is dropped. TBH I'm not sure how enabling masquerading would have worked unless there was a bug in cilium 1.11 that has been fixed in 1.14.

With masquerading disabled, almost all of the failing tests pass. The only remaining failures are unrelated to pod networking.

[k8s-ci-robot]

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[rifelpet]

/test pull-kops-e2e-cni-cilium-eni

[hakman]

/test pull-kops-e2e-cni-cilium-eni

[k8s-ci-robot]

@rifelpet: The following tests failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
pull-kops-e2e-k8s-gce-cilium	0377987	link	true	/test pull-kops-e2e-k8s-gce-cilium
pull-kops-e2e-cni-cilium-ipv6	0377987	link	false	/test pull-kops-e2e-cni-cilium-ipv6
pull-kops-e2e-cni-cilium-etcd	0377987	link	true	/test pull-kops-e2e-cni-cilium-etcd
pull-kops-e2e-cni-cilium	0377987	link	true	/test pull-kops-e2e-cni-cilium
pull-kops-e2e-cni-cilium-eni	0377987	link	false	/test pull-kops-e2e-cni-cilium-eni

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[k8s-ci-robot]

PR needs rebase.

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