test: K8sUpdates: Remove deprecated code

[pchaigno]

K8sUpdates now only tests upgrade and downgrades between 1.9 and master, so code to handle Cilium <1.8 can be removed.

[pchaigno]

test-me-please

[joestringer]

Actually, one question: Before there were "default" cases in the switch case, shouldn't the new version of the code just retain that piece and drop the other parts?

[pchaigno]

Before there were "default" cases in the switch case, shouldn't the new version of the code just retain that piece and drop the other parts?

Good question 😸 The default case sets debug.enabled=false and devices=privateIface.

devices is already set in

cilium/test/helpers/kubectl.go

Lines 2369 to 2379 in 049b611

	// Set devices
	privateIface, err := kub.GetPrivateIface()
	if err != nil {
	return err
	}
	defaultIface, err := kub.GetDefaultIface()
	if err != nil {
	return err
	}
	devices := fmt.Sprintf(`'{%s,%s}'`, privateIface, defaultIface)
	addIfNotOverwritten(options, "devices", devices)

although with a slightly different value. The K8sUpdates test passes on net-next and 4.19 so I don't think the slight difference is an issue.

debug.enabled was set to false to disable the datapath's debug mode. The agent and datapath debug modes are now separate and datapath debug mode is already disabled by default. So this change isn't needed anymore.

[pchaigno]

Unrelated tests failed in https://jenkins.cilium.io/job/Cilium-PR-K8s-1.19-kernel-4.19/4976/ because of #15337. All reviews are in. Marking as ready to merge.