[BUGFIX] ResourceCompressor must deal with absolute web paths

ResourceCompressor lacks the ability to compress files which are
registered with their absolute web path (as FormEngine does).
Add a check to resolve such paths correctly.

Resolves: #78803
Releases: master
Change-Id: Id42b0889243e898dfb01a018974e5db51675a15b
Reviewed-on: https://review.typo3.org/50782


Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: Georg Ringer <georg.ringer@gmail.com>
Reviewed-by: Joerg Boesche <typo3@joergboesche.de>
Reviewed-by: Benni Mack <benni@typo3.org>
Tested-by: Benni Mack <benni@typo3.org>
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Tested-by: Wouter Wolters <typo3@wouterwolters.nl>