Currently when we run test flows with kind, we run kubetest2 kind --up --down which will also delete the kind cluster after the test flow finishes in the normal way. But if the Prow job is interrupted in the middle, the cluster will not be properly deleted thus will be causing memory leakage, as described in kubernetes-sigs/kind#303 (comment)
We should add a trap command to make sure the cluster can still be cleaned up even when the Prow job is interrupted.