remove unused hack/* files

- hack/test-cri-integration.sh : called from Makefile
- hack/test-utils.sh : called from hack/test-cri-integration.sh
- hack/utils.sh : called from hack/test-utils.sh

Other files are no longer used and can be safely removed.

Kube test-infra doesn't seem to require the removed file as well: https://github.com/kubernetes/test-infra/search?q=containerd+hack

Signed-off-by: Akihiro Suda <[email protected]>

Author: AkihiroSuda