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>.

remove incorrect static restmapper from type registry

A RESTMapping can only be determined by inspecting a server since discovery is the authoritative source of mapping decisions.  This removes a deceptive method from the type registry and makes the old logic available for existing tests in a separate, clearly labeled package.

@kubernetes/sig-api-machinery-pr-reviews @kubernetes/sig-cli-maintainers 

```release-note
NONE
```