[TASK] Streamline InstallUtilityTest

Avoid mocking not existing methods in one
test. Remove two other tests that mock so
much that it's very hard to understand
what they try to achieve in the first place.

Resolves: #100417
Related: #100249
Releases: main
Change-Id: I213f82989cbf5d170b8ca68320c8ab2c10a9efef
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/78388


Tested-by: core-ci <typo3@b13.com>
Tested-by: Benni Mack <benni@typo3.org>
Tested-by: Oliver Klee <typo3-coding@oliverklee.de>
Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>
Reviewed-by: Benni Mack <benni@typo3.org>