Bug 24817: Add sleep between db create actions

Bug 24817: Add sleep between db create actions

We need to allow some time to pass between calls that add cash register
lines to accountlines or cash_register_actions. We use database level
triggers to maintain the timestamp fields, so cannot use Time::Fake, and
the methods we are testing assume that, as human interactions, there
will be at least a second between the last 'sale' on a cash register and
the 'cashup' of that same cash register.

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>