Bug 12738: (regression tests) C4::Context should set keyword search as default for...

Bug 12738: (regression tests) C4::Context should set keyword search as default for QueryParser

This patch introduces tests for the QueryParser PQF driver usage in Koha. Specifically its
initialization on C4::Context, and initial setup.

It also introduces a .pl script that is used to load C4::Context with different hash randomization
seeds on purpose, to verify the initialization result is deterministic and consistent between
runs.

To test:
  $ prove -v t/db_dependent/QueryParser.t

It should fail because different default_search_class is set on each run, and it is not often the
one we expect.

Sponsored-by: Universidad Nacional de Cordoba
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Katrin Fischer <Katrin.Fischer.83@web.de>
Signed-off-by: Tomas Cohen Arazi <tomascohen@gmail.com>