[TASK] Add more UnitTests for GeneralUtility::xml2array()

Resolves: #83578
Related: #83580
Releases: master
Change-Id: I2c97edd4bac854b33501ba571ed479bdefc288d7
Reviewed-on: https://review.typo3.org/55373


Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Jigal van Hemert <jigal.van.hemert@typo3.org>
Tested-by: Jigal van Hemert <jigal.van.hemert@typo3.org>