Test downgrade of data files from the 4.4 format with prepare modifications to be read on 4.2 systems. We expect that this will be ad hoc testing, rather than creating a runnable test case.  (The latter is designed to run on a single version of the system, rather than two versions, as is needed for downgrade testing).

WT-5669 already includes some "quick and dirty" testing of reading 4.2 files, this ticket is targeted to more complete testing with actual files created by 4.4 once this epic has been implemented enough to create data files containing the new elements.