refactor(netx): use netxlite for AddressResolver (#500)

Part of https://github.com/ooni/probe/issues/1591.

internal/engine/netx/resolver/address.go

@@ -1,22 +1,9 @@
 package resolver
 
 import (
-	"context"
-	"net"
+	"github.com/ooni/probe-cli/v3/internal/netxlite"
 )
 
 // AddressResolver is a resolver that knows how to correctly
 // resolve IP addresses to themselves.
-type AddressResolver struct {
-	Resolver
-}
-
-// LookupHost implements Resolver.LookupHost
-func (r AddressResolver) LookupHost(ctx context.Context, hostname string) ([]string, error) {
-	if net.ParseIP(hostname) != nil {
-		return []string{hostname}, nil
-	}
-	return r.Resolver.LookupHost(ctx, hostname)
-}
-
-var _ Resolver = AddressResolver{}
+type AddressResolver = netxlite.AddressResolver

internal/engine/netx/resolver/address_test.go

@@ -1,36 +0,0 @@
-package resolver_test
-
-import (
-	"context"
-	"errors"
-	"testing"
-
-	"github.com/ooni/probe-cli/v3/internal/engine/netx/resolver"
-)
-
-func TestAddressSuccess(t *testing.T) {
-	r := resolver.AddressResolver{}
-	addrs, err := r.LookupHost(context.Background(), "8.8.8.8")
-	if err != nil {
-		t.Fatal(err)
-	}
-	if len(addrs) != 1 || addrs[0] != "8.8.8.8" {
-		t.Fatal("not the result we expected")
-	}
-}
-
-func TestAddressFailure(t *testing.T) {
-	expected := errors.New("mocked error")
-	r := resolver.AddressResolver{
-		Resolver: resolver.FakeResolver{
-			Err: expected,
-		},
-	}
-	addrs, err := r.LookupHost(context.Background(), "dns.google.com")
-	if !errors.Is(err, expected) {
-		t.Fatal("not the error we expected")
-	}
-	if addrs != nil {
-		t.Fatal("expected nil addrs")
-	}
-}