tests/shell: better naming for test categories
tests/shell: better naming for test categories

One test was removed, because the intended test case is
already covered by check_line_exceeded

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