Bug 34912: Add 14 hours to 1970 date in Account(s).t

Bug 34912: Add 14 hours to 1970 date in Account(s).t

This makes those tests pass in whatever timezone.

Test plan:
Do not yet apply patch.
Change timezone on commandline with: export TZ='Etc/GMT-14'
NOTE: GMT-14 is what we also call UTC+14 (sign reversed).
Run prove t/db_dependent/Accounts.t t/db_dependent/Koha/Account.t
This fails now.
Apply patch.
Rerun tests and verify that they pass now.
Bonus: Try some other time zone.

Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
(cherry picked from commit 8d4b10fc846eb74aa381c809923d13bf258a9752)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>