Automatic merge from submit-queue (batch tested with PRs 65348, 65599, 65635, 65688, 65691). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

test/e2e_node/system/types_unix: support ZFS

**What this PR does / why we need it**:

Docker validation tests in the case of ZFS used as the graph driver
fail due to "zfs" not being present in the default Docker specification.

Add "zfs" in the GraphDriver slice.

kubeadm relies on the `DockerValidator` and pre-flight checks would fail if the user is using ZFS.

**Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close the issue(s) when PR gets merged)*:
Updates kubernetes/kubeadm#930

**Special notes for your reviewer**:
NONE

/cc @kubernetes/sig-node-pr-reviews 
/cc @kubernetes/sig-cluster-lifecycle-pr-reviews 
/cc @kvaps (reported by)
/area node-e2e
/area kubeadm

**Release note**:

```release-note
Unix: support ZFS as a valid graph driver for Docker
```