fdo#73606: Avoid excessive and unnecessary heap allocation of array objects.

This is a leftover from the 1 million row conversion we did years ago.

Change-Id: Ib50819ed51c7017bcc559bfc8b6062ff46615d09
(cherry picked from commit df9243626b39742a9a148bea95796f8824fee68a)
Reviewed-on: https://gerrit.libreoffice.org/7425
Reviewed-by: Markus Mohrhard <markus.mohrhard@googlemail.com>
Tested-by: Markus Mohrhard <markus.mohrhard@googlemail.com>