In test case 4 for extent maps, if we error out we are supposed to print
in interval but instead of printing a non-inclusive end offset, we are
printing the length of the interval, which makes it confusing. So fix
that to print the exclusive end offset instead.
Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>