net: fix TestDialerLocalAddr on Plan 9

We cannot use "0.0.0.0" (IPv4) or "::" (IPv6) for local address, so
don't use those addresses in the control message. Alternatively, we
could've used "*" instead.

Fixes #39931

Change-Id: Ib2dcbb1a0c648296c3ecaddbe938053a569b1f1b
Reviewed-on: https://go-review.googlesource.com/c/go/+/240464


Run-TryBot: David du Colombier <0intro@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David du Colombier <0intro@gmail.com>