[TASK] Avoid extending other test classes

Test classes (*.Test.php) should not extend
each other. If really needed, they can rely
on abstracts (Abstract*TestCase.php) files
for common functionality.

Also, .csv fixture files shouldn't be
cross used between extensions and
functional and functionalDeprecated
directories to avoid dead files.

Avoid this for a deprecated test case.

Resolves: #100523
Releases: main
Change-Id: I00d9ca57cbfc90f4b4e412859e72ae3b55f2fadb
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/78531


Tested-by: core-ci <typo3@b13.com>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>
Tested-by: Oliver Klee <typo3-coding@oliverklee.de>