[TASK] Doctrine: Migrate functional test cases in ext:core

The removed IRRE\AbstractTestCase was a left-over from the initial
functional test introduction with TYPO3 CMS 6.2 that was refactored
later on and has not been used any further.

Adjustments in the asserted test values have been necessary since
previously data has been retrieved as string and is now implicitly
casted to double for accordant database column types.

Resolves: #77507
Releases: master
Change-Id: I2aaf493f4401c7eb438b948dfe450acb52411451
Reviewed-on: https://review.typo3.org/49490


Tested-by: Bamboo TYPO3com <info@typo3.com>
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: Georg Ringer <georg.ringer@gmail.com>
Reviewed-by: Oliver Hader <oliver.hader@typo3.org>
Tested-by: Oliver Hader <oliver.hader@typo3.org>