This is a manual cherry-pick (with some changes) from !60899 (merged). A more detailed description of the problem solved (and also described in ATLASG-2456) is in that ticket.
@krumnack, I found it curious how this 21.2 branch uses JobOptionsSvc differently from the master branch. What surprised me most is that this branch, naively, seems to do a better job.
At the same time I enabled the same two unit tests for AnalysisBase that the package now uses in master as well.
This is not strictly necessary for 21.2 as far as I understand. The same dictionary issue that hits us in master is not present with the ROOT version used in this branch. But it may still be a good idea not to let the two branches diverge on this.