[TASK] Remove needless check function in language module

This patch removes the check function and related to that, the use of
the caching framework.

Resolves: #41824
Related: #39963
Releases: 6.0

Change-Id: I3d3de72c287a9b1167f0d1ea563f16994fd0ffe3
Reviewed-on: http://review.typo3.org/15475
Reviewed-by: Wouter Wolters
Tested-by: Wouter Wolters
Reviewed-by: Christian Kuhn
Tested-by: Christian Kuhn