--wait=true exits prematurely, breaks conformance test script

[tstromberg]

NOTE: This is not a discussion about defaults, this is about the behavior when explicitly setting --wait=true.

The ./hack/conformance_tests.sh script is broken because Kubernetes is not actually up yet:

+ kubectl --context k8sconformance get pods --all-namespaces
NAMESPACE     NAME                                     READY   STATUS    RESTARTS   AGE
kube-system   etcd-k8sconformance                      0/1     Pending   0          7s
kube-system   kube-apiserver-k8sconformance            0/1     Pending   0          7s
kube-system   kube-controller-manager-k8sconformance   1/1     Running   0          7s
kube-system   kube-scheduler-k8sconformance            1/1     Running   0          7s
kube-system   storage-provisioner                      0/1     Pending   0          2s
...
+ sonobuoy run --wait
WARN[0000] The maximum supported Kubernetes version is 1.17.99, but the server version is v1.18.0. Sonobuoy will continue but unexpected results may occur. 
ERRO[0000] Preflight checks failed                      
ERRO[0000] no dns pods found with the labels [k8s-app=kube-dns, k8s-app=coredns] in namespace kube-system

[tstromberg]

Related to #7209