net: don't recheck goosPrefersCgo in hostLookupOrder

net: don't recheck goosPrefersCgo in hostLookupOrder

We only did it for testing. Remove the single test that required it.

Change-Id: Ib6c3a2debfd3f48e95af37f23fdfde847ff87a41
Reviewed-on: https://go-review.googlesource.com/c/go/+/490395
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Bryan Mills <bcmills@google.com>
Reviewed-by: Damien Neil <dneil@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>