[CLEANUP] setUp and tearDown should be protected

setUp and tearDown are protected in the PHPUnit base classes.
There is no reason to make them public in the generated unit tests.

Releases: 6.2
Resolves: #58083

Change-Id: If1228e5ff8ff628e012e59467429d49d3ac48913
Reviewed-on: https://review.typo3.org/29602
Reviewed-by: Nico de Haen
Tested-by: Nico de Haen