Change 22019
Fix TaskListener serialisation issue.
TaskListener field must be transient as part of the program state, but is marked `Serializable` for the Task as it is sent over the Remoting Channel.
Update p4 groovy to extend Step and not AbstractStepImpl.
TaskListener field must be transient as part of the program state, but is marked `Serializable` for the Task as it is sent over the Remoting Channel.
Update p4 groovy to extend Step and not AbstractStepImpl.