Automatic merge from submit-queue. 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>.
fix controlplane unit tests
What this PR does / why we need it:
when the flexvolumeDirVolumePath is truely existent in the host,
```cmd/kubeadm/app/phases/controlplane``` unit tests will be failed.
Fixes#56189
Release note:
```release-note
NONE
```
362e6293ce