net: don't rely on system hosts in TestCVE202133195
net: don't rely on system hosts in TestCVE202133195

Also don't unnecessarily deref the error return.

Fixes #46504

Change-Id: I22d14ac76776f8988fa0774bdcb5fcd801ce0185
Reviewed-on: https://go-review.googlesource.com/c/go/+/324190
Trust: David Chase <ae171625adc8645b8b79b7e405a6da5aba5341e0@google.com>
Trust: Damien Neil <7e091e9a80da888fcd7836fd3c6b7b85f4677c12@google.com>
Run-TryBot: David Chase <ae171625adc8645b8b79b7e405a6da5aba5341e0@google.com>
TryBot-Result: Go Bot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>
Reviewed-by: Damien Neil <7e091e9a80da888fcd7836fd3c6b7b85f4677c12@google.com>

nawawi/go,golang/go,nawawi/go,CAFxX/go,cloudflare/go,nawawi/go,golang/go,golang/go,cloudflare/go,CAFxX/go,cloudflare/go,cloudflare/go,golang/go,CAFxX/go,CAFxX/go,CAFxX/go,nawawi/go,golang/go,nawawi/go,cloudflare/go,golang/go,CAFxX/go,nawawi/go,nawawi/go,golang/go,nawawi/go,cloudflare/go,CAFxX/go,golang/go,cloudflare/go,cloudflare/go,CAFxX/go