provision: always use a large transaction index cache

provision: always use a large transaction index cache

A larger cache costs more per transaction, but makes a large number
of operations within a transaction faster. We expect to be dealing
with the latter case here, regardless of the batch_mode parameter
and the database size. 200000 is chosen because it is also used in
join and schemaupgrade, and should be sufficient in most cases.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=15795

Signed-off-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
Autobuild-User(master): Douglas Bagnall <dbagnall@samba.org>
Autobuild-Date(master): Tue Feb  4 22:47:35 UTC 2025 on atb-devel-224

(cherry picked from commit e705dbbc6765454813375fee9f6a3365b947e021)

Autobuild-User(v4-21-test): Jule Anger <janger@samba.org>
Autobuild-Date(v4-21-test): Thu Feb 27 12:10:52 UTC 2025 on atb-devel-224