In order to implement repair tests, changes are made to the
`constraint_check` table to simulate a broken dependency, which
requires the constraints on that table to be dropped. This means that
the repair runs without constraints, and a bug in the update test could
potentially not get caught.
This commit fixes this by factoring out the repair tests from the
update tests and run them as a separate pass. This means that the
contraints are not dropped in the update tests and bugs there will be
caught.
In addition, some bash functions are factored out into a separate file
to avoid duplication.
