Currently, the regression tests tied to the MachineConfigNode (MCN) Feature Gate (FG) are run as part of the default parallel and serial suites for openshift/origin. With the creation of an MCO-specific disruptive test suite in MCO-1652, all MCO tests were moved into that test suite. Once MCO-1679 is complete and the MCO disruptive suite runs on an automated schedule, the MCN tests should be monitored, especially those not previously enabled (MCO-1597 & MCO-1598), and fixed or updated as necessary.

This task should also serve as the opportunity to clean up some code in the tests with room for improvements, which have been detailed in the "Done when" section.

Done when:

• All tests related to the MCN FG are successfully running in the MCO disruptive test suite.
• Code improvements are made, where appropriate.
  • Update the `CleanupCustomMCP` function so that it does not take in a `nodeName` parameter. Rather, the node(s) to unlabel should be determined within the function by grabbing all nodes in the custom MCP.
    • More details can be found here & in this slack thread.
  • Update the MCP name constants to have more descriptive names. For example, `worker` could be renamed as `mcPoolNameWorker`, `poolNameWorker`, or `workerMCPName`, just a name that's a bit more descriptive than it currently is. 
    • See this comment on GitHub & the above Slack thread for more context.