docker: Update Dockerfile
docker: Update Dockerfile

 - openjdk8 is removed from deps.
 - the image size is about 596MB.

dreal/dreal4,soonho-tri/dreal4,soonho-tri/dreal4,dreal/dreal4,dreal/dreal4,dreal/dreal4,soonho-tri/dreal4,soonho-tri/dreal4