add new test for *read-suppress*
According to the example in the CLHS documentation on *read-suppress* (http://www.lispworks.com/documentation/HyperSpec/Body/v_rd_sup.htm), undefined macro dispatch characters should not signal an error.
According to the example in the CLHS documentation on *read-suppress* (http://www.lispworks.com/documentation/HyperSpec/Body/v_rd_sup.htm), undefined macro dispatch characters should not signal an error.