[TASK] Add functional tests for hreflang tag generation

To make sure rendering of hreflang tags will not change unexpectedly,
some functional tests are added.

Resolves: #88251
Related: #88140
Releases: master, 9.5
Change-Id: Idd8bc846e4bd57eb5335fe4795dcb233849eb4e8
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/60635


Tested-by: Benni Mack <benni@typo3.org>
Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Jonas Eberle <flightvision@googlemail.com>
Tested-by: Tymoteusz Motylewski <t.motylewski@gmail.com>
Reviewed-by: Benni Mack <benni@typo3.org>
Reviewed-by: Tymoteusz Motylewski <t.motylewski@gmail.com>