Delete test_illegal_objects, now that we're using schema_worker,
there's no special path for illegal objects and no reason to do
any special testing.
Re-work the code to build the target list, uncomment object checking,
this now works.
We have to write all of the names/value pairs out to the backup file,
not just the file: objects, don't discard the trailng ".wt" from the
file object name, whatever is in the metadata file is what we use.