tests/shell: don't expect idle thread in ps output
tests/shell: don't expect idle thread in ps output

miri64/RIOT,kYc0o/RIOT,ant9000/RIOT,jasonatran/RIOT,RIOT-OS/RIOT,jasonatran/RIOT,authmillenon/RIOT,OlegHahm/RIOT,authmillenon/RIOT,jasonatran/RIOT,kYc0o/RIOT,ant9000/RIOT,kaspar030/RIOT,ant9000/RIOT,miri64/RIOT,authmillenon/RIOT,OlegHahm/RIOT,ant9000/RIOT,miri64/RIOT,kYc0o/RIOT,authmillenon/RIOT,authmillenon/RIOT,authmillenon/RIOT,kaspar030/RIOT,jasonatran/RIOT,jasonatran/RIOT,OTAkeys/RIOT,OlegHahm/RIOT,kYc0o/RIOT,RIOT-OS/RIOT,OlegHahm/RIOT,miri64/RIOT,OTAkeys/RIOT,kaspar030/RIOT,kaspar030/RIOT,OTAkeys/RIOT,miri64/RIOT,kaspar030/RIOT,OlegHahm/RIOT,RIOT-OS/RIOT,ant9000/RIOT,kYc0o/RIOT,RIOT-OS/RIOT,RIOT-OS/RIOT,OTAkeys/RIOT,OTAkeys/RIOT