Revert changes making HSQLDB related unit tests test Firebird migration.
They should still test the HSQLDB driver.

It reverts part of 159dd286

Change-Id: If2b9207e95055418bd1dc1dc6e472335de311d1e
Reviewed-on: https://gerrit.libreoffice.org/52873Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Tamás Bunth <btomi96@gmail.com>