Fix cp23205 check for invalid command in system()
Fix cp23205 check for invalid command in system()

IronLanguages/ironpython2,slozier/ironpython2,slozier/ironpython2,IronLanguages/ironpython2,IronLanguages/ironpython2,slozier/ironpython2,IronLanguages/ironpython2,slozier/ironpython2,slozier/ironpython2,slozier/ironpython2,IronLanguages/ironpython2,IronLanguages/ironpython2,IronLanguages/ironpython2,slozier/ironpython2