[TASK] Extend Testbase to run functionals tests with multiple DB drivers

Implement Testbase::importXmlDatabaseFixtureFinisher to handle database
platform specific cleanup tasks for functional tests. For PostgreSQL
this will update the primary key sequences to the maximum value used
in the table to avoid key errors on subsquent inserts.

This patch doesn't fix all functional test to work on PostgreSQL, this
will follow in smaller, subsequent patches as many tests currently fail
due to database rows being returned in a different order as well as
due to different return types of the databases (i.e. int vs. string)
leading to failures when using assertSame().

Releases: master
Resolves: #79650
Change-Id: I8a08fc033b638eb66ca7655fdde4f311dd5982b2
Reviewed-on: https://review.typo3.org/51152


Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Morton Jonuschat <m.jonuschat@mojocode.de>
Tested-by: Morton Jonuschat <m.jonuschat@mojocode.de>
Reviewed-by: Thomas Hohn <thomas@hohn.dk>
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>