More tests.

[monopole]

To RNode add methods

Get/SetNamespace
Get/SetLabels
Get/SetAnnotations

These setters completely remove the field if the argument
is empty, rather than setting the field to an empty value,
mimicing apimachinery behavior.

The implementations in WNode are supposed to be thin, as they are temporary.
This means pushing logic down to RNode.

This is generally in service of #2915.

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: monopole

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [monopole]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[k8s-ci-robot]

@monopole: The following test failed, say /retest to rerun all failed tests:

Test name	Commit	Details	Rerun command
kustomize-presubmit-master	1be9b94	link	/test kustomize-presubmit-master

Full PR test history. Your PR dashboard. Please help us cut down on flakes by linking to an open issue when you hit one in your PR.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository. I understand the commands that are listed here.