jspec: protect against nan values which can not get converted to json
jspec: protect against nan values which can not get converted to json

mkeilman/sirepo,mkeilman/sirepo,radiasoft/sirepo,mkeilman/sirepo,mrakitin/sirepo,mkeilman/sirepo,radiasoft/sirepo,mrakitin/sirepo,mrakitin/sirepo,radiasoft/sirepo,radiasoft/sirepo,radiasoft/sirepo,mrakitin/sirepo