bench() fix now that forder returns integer() rather than NULL.
bench() fix now that forder returns integer() rather than NULL.

vlulla/data.table,Rdatatable/data.table,jangorecki/data.table,vlulla/data.table,vlulla/data.table,Rdatatable/data.table,jangorecki/data.table,jangorecki/data.table,jangorecki/data.table,Rdatatable/data.table,Rdatatable/data.table,vlulla/data.table