a linear loop builds a recursive structure, if it gets too deep then later
processing, e.g. releasing the tree, can exhaust stack

Change-Id: I4421b9bae62ac2b6ffe32531d1167a482103bfde
Reviewed-on: https://gerrit.libreoffice.org/54762Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>