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 log collection for kubeadm-gce tests

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

Separate out kuberenetes-anywhere provider under cluster/ but
delegate all the functionality to the "gce" one since the code
would be the same. Except for the name of the node, the
NODE_INSTANCE_PREFIX will be different, so account for that.


**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes #

**Special notes for your reviewer**:

**Release note**:

```release-note
NONE
```