SCM poll in the crw-theia-sources_2* job is running too often, thinking that SCM changes have occurred.

Build yesterday https://main-jenkins-csb-crwqe.apps.ocp4.prod.psi.redhat.com/job/CRW_CI/job/crw-theia-sources_2.11/96/pollingLog/ reports that the last built revisions of che-theia and crw-theia are, respectively:

[poll] Last Built Revision: Revision 782a532ed052215489d5610d610973fce17d75f8 (origin/7.34.x)
[poll] Last Built Revision: Revision 08a9bdcc85ac913bf91c882565845b26834e98df (origin/crw-2.11-rhel-8)

But then goes on to complain that:

no polling baseline in /var/lib/jenkins/workspace/CRW_CI/crw-theia-sources_2.11 on crw-agent-node-2
no polling baseline in /var/lib/jenkins/workspace/CRW_CI/crw-theia-sources_2.11 on crwjen-3.s390
no polling baseline in /var/lib/jenkins/workspace/CRW_CI/crw-theia-sources_2.11 on crwjen-ppc-1

So... it runs a fresh build, despite the fact that the commits above are ~2 weeks old:

• https://github.com/eclipse-che/che-theia/commits/7.34.x Aug 11
• https://github.com/redhat-developer/codeready-workspaces-theia/commits/crw-2.11-rhel-8 Aug 13

I suspect the problem could be that the job is configured to poll on too many machines (should only poll on a single static box, like crwjen-1). Or the git clone commands for the individual per-arch builds are set to poll (when they should not).