[BUGFIX] synchronize flags in registry with TCA

Flag icons that come with core, the flags that are registered in the icon
registry, the lists in sys_language and site_language are now in sync again.

Releases: master
Resolves: #86460
Change-Id: I1e274b3e274b305486b6e37d600a915177ef484c
Reviewed-on: https://review.typo3.org/58476


Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Benni Mack <benni@typo3.org>
Tested-by: Benni Mack <benni@typo3.org>
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>