[BUGFIX] Fix basename-fetch in basenameDuringBootstrap

Also add tests for dirnameDuringBootstrap and basenameDuringBootstrap.

Resolves: #84988
Related: #74806
Releases: master
Change-Id: I6544435f6c79425e7c008670cc5dd4df355b28c8
Reviewed-on: https://review.typo3.org/56944


Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Andreas Wolf <andreas.wolf@typo3.org>
Tested-by: Andreas Wolf <andreas.wolf@typo3.org>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>