Compatibility Version E2E Test Currently Use Kubelet at Version "N" But They Should use a Kubelet At Version N-1

[aaron-prindle]

What happened:
Currently the Compatibility Versions E2E Test runs a kind cluster @ version "N" (k8s latest) and then sets --emulated-version=n-1 for the kube-apiserver, kube-scheduler, and kube-controller manager. This means the kubelet is still at version N but to properly test the component versions we would encounter in common usage ( for upgrade scenarios) the kubelet should be at version N-1. As such we currently have a test gap.

What you expected to happen:
I expect that the Compatibility Version E2E Test properly test the k8s component versions that would be encountered in common usage (for upgrade scenarios) and in that case the kubelet binary should be version n-1

How to reproduce it (as minimally and precisely as possible):
Run the test at https://github.com/kubernetes/test-infra/blob/master/config/jobs/kubernetes/sig-testing/compatibility-versions-e2e.yaml (calls https://github.com/kubernetes/test-infra/blob/master/experiment/compatibility-versions/e2e-k8s-compatibility-versions.sh). Check the version of the kubelet that is run

/assign @aaron-prindle
/sig api-machinery