AthAnalysis Fixes, master branch (2020.12.17.)

These are a couple of improvements for the tests run in the AthAnalysis project.

https://bigpanda.cern.ch/nview/?nightly=master_AthAnalysis_x86_64-centos7-gcc8-opt

Note that this is just scratching the surface at this point. We still have a lot of things to clean up in that project before it would be test-failure-free...