test: don't connect to 0.0.0.0

OpenBSD won't let you do that, the connect() system call fails with
an EINVAL error.  Connect to 127.0.0.1 instead.
netbsd, openbsd: enable futimes() wrapper

OpenBSD and NetBSD have working futimes() implementations.  This commit
makes uv_fs_futime() work on those platforms.