tdbtorture: Fix CID 1034816: proper calloc usage

tdbtorture: Fix CID 1034816: proper calloc usage

Standard signature is 'calloc(n_elems, elem_size)', where element size
(in particular, when using 'sizeof') comes as 2nd arg. The actual
allocation size does not care for ordering but swapping the order
confuses static-analysis tools like Coverity, as well as naive readers.

Signed-off-by: Shachar Sharon <ssharon@redhat.com>
Reviewed-by: Vinit Agnihotri <vagnihot@redhat.com>
Reviewed-by: Shweta Sodani <ssodani@redhat.com>
Reviewed-by: Rabinarayan Panigrahi <rapanigr@redhat.com>
Reviewed-by: Anoop C S <anoopcs@samba.org>
Reviewed-by: Guenther Deschner <gd@samba.org>
Reviewed-by: Volker Lendecke <vl@samba.org>
Autobuild-User(master): Günther Deschner <gd@samba.org>
Autobuild-Date(master): Tue Aug 19 18:08:02 UTC 2025 on atb-devel-224