Automatic merge from submit-queue
Check for an empty value in validateField
```release-note
* Fix a panic when args was not supplied with any values.
```
reflect.TypeOf() can take a nil (it then returns a nil), but
Kind() panics on a nil.
Now the user gets the following output:
./kubectl.sh --server=http://localhost:8080 create -f ../../test-files/test-rc.yaml
error validating "../../test-files/test-rc.yaml": error validating data: unexpected nil value for field spec.template.spec.containers[0].args[0]; if you choose to ignore these errors, turn validation off with --validate=false
fixes#20627 and fixes#26927
b4c81a073a