Automatic merge from submit-queue
Make a vSphere cluster the failure_zone
vSphere cloud provider returns the FailureZone as Cluster, if the VM belongs to a ResourcePool under a Cluster.
fixes: #30933
* Currently the vSphere cloud provider treats Datacenter as the failure
Zone. This doesn't necessarily work since in the current implemention
Kubernetes nodes cannot span Datacenters.
* This change introduces Clusters as the failure zone, while treating
Datacenters as Regions
* Also updated tests for Zones