fuzzy: disallow post-test online rebuilds when testing online fsck

fuzzy: disallow post-test online rebuilds when testing online fsck

If we're testing the online fsck code or running fuzz tests of the
filesystem, don't let the post-test checks rebuild the filesystem
metadata, because this is redundant with the test and will disturb
the metadata if the tools fail.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Andrey Albershteyn <aalbersh@redhat.com>
Reviewed-by: Zorro Lang <zlang@redhat.com>
Signed-off-by: Zorro Lang <zlang@kernel.org>