Merge branch 'filesize-mc16a' into '21.0-mc16a'

Add a helper postInclude to disable file size limit (MC16a)

See merge request !46571

Tools/PyJobTransforms/share/DisableFileSizeLimit.py

+# Copyright (C) 2002-2021 CERN for the benefit of the ATLAS collaboration
+#
+# Disable file size limit for POOL files
+
+from AthenaCommon.AppMgr import ServiceMgr
+if hasattr(ServiceMgr, "AthenaPoolCnvSvc"):
+    ServiceMgr.AthenaPoolCnvSvc.MaxFileSizes = ["150000000000"]  # set to 150 GB