[BUGFIX] Detect current ImageMagick Version 7 for Windows.

Try to use magick.exe if executable does not exists.

ImageMagick Version 7 for Windows does not use the executables for
identify, convert and combine/composite anymore. Instead the executable
magick.exe is used.

Resolves: #80909
Releases: master, 8.7
Change-Id: I823d399b723077e726b1105192474607b43fa907
Reviewed-on: https://review.typo3.org/57805


Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Guido Schmechel <guido.schmechel@brandung.de>
Tested-by: Guido Schmechel <guido.schmechel@brandung.de>
Reviewed-by: Jigal van Hemert <jigal.van.hemert@typo3.org>
Tested-by: Jigal van Hemert <jigal.van.hemert@typo3.org>