convert linked list to std::vector in SbxDimArray

Change-Id: I2640cfe1f9606d992f622b99ff3c607555771e23
Reviewed-on: https://gerrit.libreoffice.org/10298
Reviewed-by: Michael Stahl <mstahl@redhat.com>
Tested-by: Michael Stahl <mstahl@redhat.com>