tests/fate-run: Allow to skip file checksums for lavf_image

tests/fate-run: Allow to skip file checksums for lavf_image

The output file (even the filesize) of the recently added
EXR tests depends on the endianness; therefore checksums
of these files must not be part of the ref file. Therefore
this commit adds an option (unused for now) to disable these
checksums on a per-test basis.

In order to avoid having to check twice, the checksum and
the filesize info are moved to immediately follow one another;
this results into updates to the ref files of all lavf-image tests.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
(cherry picked from commit 4fb8741c4670965eaf1f78d6122c6bdfdf1f3358)

Gbp-Pq: Name 0005-tests-fate-run-Allow-to-skip-file-checksums-for-lavf.patch