Automatic merge from submit-queue (batch tested with PRs 66850, 66902, 66779, 66864, 66912). 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>.
add methods to apimachinery to easy unit testing
When unit testing, you often want a selective scheme and codec factory. Rather than writing the vars and the init function and the error handling, you can simply do
`scheme, codecs := testing.SchemeForInstallOrDie(install.Install)`
@kubernetes/sig-api-machinery-misc
@sttts
```release-note
NONE
```
4a54f3f0d6