As of now, the kubelet is passing the security context to container runtime even
if the security context has invalid options for a particular OS. As a result,
the pod fails to come up on the node. This error is particularly pronounced on
the Windows nodes where kubelet is allowing Linux specific options like SELinux,
RunAsUser etc where as in [documentation](https://kubernetes.io/docs/setup/production-environment/windows/intro-windows-in-kubernetes/#v1-container),
we clearly state they are not supported. This PR ensures that the kubelet strips
the security contexts of the pod, if they don't make sense on the Windows OS.
WaitForPod*() are just wrapper functions for e2epod package, and they
made an invalid dependency to sub e2e framework from the core framework.
So this replaces WaitForPodTerminated() with the e2epod function.
Currently, Kubernetes supports running as different user (RunAsUser),
but it only supports UIDs, which does not work on Windows.
Which is why the field SecurityContext.WindowsOptions.RunAsUserName
was introduced, to allow us to run the container entrypoints with
a different user than its default one.
This commit adds E2E tests which will validate this behaviour. The
tests are Windows only, and they will be skipped if --node-os-distro
is not "windows".
