riotctrl_shell.tests: rewrite Mock to detect missing check_term
riotctrl_shell.tests: rewrite Mock to detect missing check_term

`check_term` calls `run_term` of the `ctrl` if necessary.

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