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>.

Regional support in Cluster Autoscaler e2e tests.

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

When calling GKE API and gcloud in Autoscaling e2 tests, take into account that clusters can be regional.
This currently uses MultiZonal as an indicator that cluster is regional, which is suboptimal, but considering that our tests do not work with multizonal clusters at the moment, there is no regression.This should be changed once there is an indicator available that the cluster is regional.

**Release note**:
```
NONE
```