In PR #99785, I disabled a test for `epoll_create` that was intended to
fail on systems where only `epoll_create1` is available. This is because
`epoll_create1` cannot fail in the same way that `epoll_create` does.
Specifically, calling `epoll_create(0)` should result in an EINVAL
error. So, when only `epoll_create1` is available, we should simply
check if the argument is zero and return the error accordingly.
04b4f62e2f