Add a bunch of tests exercising the new btrfstune functionality. In
particular check that various restrictions are implemented correctly,
test that btrfs-image works as expected and also test the output of
btrfs inspect-internal dump-super is correct.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
