CI: e2e anti-affinity tests are red

[chrischdi]

/kind bug

What steps did you take and what happened:
[A clear and concise description of what the bug is.]

The prowjob periodic-e2e-main, the test for Cluster creation with anti affined nodes should create a cluster with anti-affined nodes is red for already a long time.
And same for the presubmit pr-full-e2e.

The issue is that there are not the required numbers of hypervisors available. To be more concrete:
The test assumes to have five hosts / hypvervisors:

cluster-api-provider-vsphere/test/e2e/anti_affinity_test.go

Line 62 in b43e70e

// Since the upstream CI has five nodes, worker node count is set to 5

But that is not the case. I tested this via #1974 which adds a check to verify there are equal or more hosts available compared to the worker count.

  [FAILED] This test requires more or equal number of hosts compared to the WorkerNodeCount. Expected at least 5 but only got 4 hosts.
  Expected
      <bool>: false

source

PR for the additional check: #1974

What did you expect to happen:

The test to succeed.

Anything else you would like to add:
[Miscellaneous information that will assist in solving the issue.]

I currently see two options:

• Lower the workerNodeCount to 4 for this job or maybe even just use the number of hosts.
• Having a look at the test infrastructure (if there is somebody having access)

Environment:

• Cluster-api-provider-vsphere version:
• Kubernetes version: (use kubectl version):
• OS (e.g. from /etc/os-release):

[sbueringer]

cc @yastij @randomvariable @srm09 Regarding: "Having a look at the test infrastructure (if there is somebody having access)"