Fix new serial constraint upgrades

Fix new serial constraint upgrades

1. None of the upgrades so far have moved is_json() from the public
to the evergreen schema.  That's probably a separate issue, but it
should be safe to call it unqualified, and that's what the rest of
the upgrade file does, so we will too.

2. Add a specific SET CONSTRAINT to avoid deferred trigger problems
when ALTERing the table.

3. Make sure that the unwanted columns on materialized_holding_code
do not exist regardless of your upgrade path.

Signed-off-by: Dan Wells <dbw2@calvin.edu>