sandboxjs.py: catch subprocess exception
sandboxjs.py: catch subprocess exception

common-workflow-language/cwltool,SciDAP/cwltool,common-workflow-language/cwltool,dleehr/cwltool,common-workflow-language/cwltool,dleehr/cwltool,SciDAP/cwltool,dleehr/cwltool,SciDAP/cwltool,dleehr/cwltool,SciDAP/cwltool