Remove runtime.Typer, reduce to ObjectKinds(1) (3)

Remove the unnecessary variants, which avoids allocations in several
core paths.

pkg/api/ref_test.go

@@ -40,7 +40,7 @@ func TestGetReference(t *testing.T) {
 	// when vendoring kube, if you don't force the set of registered versions (like this hack/test-go.sh does)
 	// then you run into trouble because the types aren't registered in the scheme by anything.  This does the
 	// register manually to allow unit test execution
-	if _, err := Scheme.ObjectKind(&Pod{}); err != nil {
+	if _, _, err := Scheme.ObjectKinds(&Pod{}); err != nil {
 		AddToScheme(Scheme)
 	}