[TASK] Add functional tests to test the caching behavior of ext:form

In preparation for patchset
https://review.typo3.org/c/Packages/TYPO3.CMS/+/70460/,
functional tests are introduced to test the caching behavior
of EXT:form.

Resolves: #97049
Related: #93887
Releases: main, 11.5
Change-Id: Ief1c8d90371d6003512f88a064c2d82e51502590
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/75082


Tested-by: core-ci <typo3@b13.com>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: Stefan Bürk <stefan@buerk.tech>
Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Reviewed-by: Stefan Bürk <stefan@buerk.tech>