[DISCUSS] Disable ptest job

[Zoltan Haindrich]

Hey all!

So far I've seen only 1 issue with the new system: there were 2 occurences in the last week when a build was affected by some kind a kubernetes issue which have taken down 
an executor - the logs pointed to some kind of kubelet issue; since the GKE master have upgraded to 1.16 while the node pools were still running 1.15 it could have been the 
cause of it. Yesterday I've upgraded all the node-pools.

Because I've seen that people now sometimes open both a PR and upload a patch to the jira as well; I would like to propose to disable the PTest job on builds.apache.org on 
Monday.

Note: This will also unblock to apply the junit5 patch - and could open up the possibility to sometimes exclude a set of tests from execution - the total test execution 
time is around 24 hours - from which 8 hours is spent running replication tests. Since most changes will touch replication stuff they could be made optional.

cheers,
Zoltan