ofz: avoid oom, tmLDIV has only two slots

Change-Id: I6df2ec0790e94008eba6a7d97256440db5a26ac7
Reviewed-on: https://gerrit.libreoffice.org/45870Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>

starmath/source/mathtype.cxx

@@ -1461,7 +1461,7 @@ bool MathType::HandleRecords(int nLevel, sal_uInt8 nSelector,
                                     sMainTerm = rRet;
                                     rRet.clear();
                                 }
-                                else
+                                else if (nPart == 1)
                                 {
                                     sPush += rRet;
                                     rRet = sPush;