Fix conversion error in bench from int -> size_t
Fix conversion error in bench from int -> size_t

MengjiaoH/ospray,MengjiaoH/ospray,ospray/OSPRay,wilsonCernWq/ospray,wilsonCernWq/ospray,MengjiaoH/ospray,ospray/OSPRay,wilsonCernWq/ospray,ospray/OSPRay,MengjiaoH/ospray,ospray/OSPRay,MengjiaoH/ospray