net: remove obsolete TestLookupHost

The motivation of TestLookupHost was to test codepaths on LookupHost,
LookupIP when we set CGO_ENABLED=1. Now we have serveral tests on those
APIs and their codepaths such as TestLookupGooglePublicDNSAddr,
TestCgoLookupIP, TestGoLookupIP, and the test using the ambiguous source
"localhost" is unnecessary.

Fixes #11182.

Change-Id: I397c823e1648114d91a229b316477bff2948b4f9
Reviewed-on: https://go-review.googlesource.com/11057
Reviewed-by: Ian Lance Taylor <iant@golang.org>

src/net/hosts_test.go

@@ -6,7 +6,6 @@ package net
 
 import (
 	"reflect"
-	"sort"
 	"testing"
 )
 
@@ -119,17 +118,3 @@ func TestLookupStaticAddr(t *testing.T) {
 		}
 	}
 }
-
-func TestLookupHost(t *testing.T) {
-	// Can't depend on this to return anything in particular,
-	// but if it does return something, make sure it doesn't
-	// duplicate addresses (a common bug due to the way
-	// getaddrinfo works).
-	addrs, _ := LookupHost("localhost")
-	sort.Strings(addrs)
-	for i := 0; i+1 < len(addrs); i++ {
-		if addrs[i] == addrs[i+1] {
-			t.Fatalf("LookupHost(\"localhost\") = %v, has duplicate addresses", addrs)
-		}
-	}
-}