In the case of multinode clusters, the http server pod and the test cluster can
spawn on different nodes, which can be problematic for poststart / prestop hooks,
as they are executed by the kubelet itself, and the cross-node lifecycle hook might
fail (according to the Kubernetes network model, it is not mandatory for kubelet to
be able to access pods on a different node).
This commit ensures that the test pod spawns on the same node as the http server pod.
