[BUGFIX] Follow-Up: Remove obsolete unit tests from test-extension fixture

Follow-up to 4226c010282b9e158044c2895d4c402a44797a27

Change-Id: I1571c3ac95fae44afbc756604dc3d759bbec4322
Resolves: #58700
Reviewed-on: https://review.typo3.org/30013
Reviewed-by: Nico de Haen
Tested-by: Nico de Haen