feat(solver/filter_assertion.cc): Cover cases with real constants
feat(solver/filter_assertion.cc): Cover cases with real constants

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