Automatic merge from submit-queue (batch tested with PRs 41112, 41201, 41058, 40650, 40926)
make round trip testing generic
RoundTrip testing is something associated with a scheme and everyone who writes an API will want to do it. In the end, we should wire each API group separately in a test scheme and have them all call this general function. Once `kubeadm` is out of the main scheme, we'll be able to remove the one really ugly hack.
@luxas @sttts @kubernetes/sig-apimachinery-pr-reviews @smarterclayton