preadv/preadv02.c: add new testcase

1) preadv(2) fails if iov_len is invalid and set errno to EINVAL.
2) preadv(2) fails if the vector count is less than zero and set errno to EINVAL.
3) preadv(2) fails if offset is negative and set errno to EINVAL.

Signed-off-by: Xiao Yang <yangx.jy@cn.fujitsu.com>
5 files changed