[BUGFIX] Tests: Incomplete mocking of $GLOBALS['TCA'] in ext:core

To reduce dependencies of tests and improve readability, some tests
can be improved by better mocking of $GLOBALS['TCA']

Change-Id: I7dee44b5a98f2384c2b77c51ebc678ff15669475
Resolves: #56696
Related: #51436
Releases: 6.2
Reviewed-on: https://review.typo3.org/28203
Reviewed-by: Wouter Wolters
Tested-by: Wouter Wolters
Reviewed-by: Anja Leichsenring
Tested-by: Anja Leichsenring