[TASK] runTests.sh: Allow step debugging acceptance tests

Honor -x option for acceptance tests: Both 'Tester' and
'System under test' allow break points with -s acceptance
and -s install.

Resolves: #93734
Releases: master
Change-Id: Ia3f5a518089be675e33ddc673ebd4c99b2dbfaf6
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/68380


Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Reviewed-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>