Automatic merge from submit-queue. If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.
Bump etcd server patch version to 3.2.16
etcd 3.2.16 contains a critical fix for HA clusters: https://github.com/coreos/etcd/pull/9281
Also, update newly added tests to use `REGISTRY` make variable.
Release note:
```release-note
Upgrade the default etcd server version to 3.2.16
```