remove nullptr CHECK_EQUAL
remove nullptr CHECK_EQUAL

this check doesn't really do anything useful for us and causes some compilers to warn about using zero as a NULL constant.
offa/cpputest,asgeroverby/cpputest,asgeroverby/cpputest,offa/cpputest,basvodde/cpputest,asgeroverby/cpputest,cpputest/cpputest,basvodde/cpputest,offa/cpputest,cpputest/cpputest,cpputest/cpputest,basvodde/cpputest,cpputest/cpputest,offa/cpputest,asgeroverby/cpputest,basvodde/cpputest