[TASK] Rename AbstractXmlSitemapPagesTest

phpunit 10 expects classes that end with "Test"
to not be abstract.

Resolves: #100483
Related: #100249
Releases: main
Change-Id: I8d3f4981d314b36f212c4368dd394c0ba2425088
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/78490


Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: core-ci <typo3@b13.com>