cleanup: netx does not use netxlite legacy names (#801)

This diff refactors netx and netxlite to ensure we're not using
netxlite legacy names inside of netx.

To this end, we're cheating a bit. We're exposing a new factory to
get an unwrapped stdlib resolver rather than defining a legacy name
to export the private name of the same factory.

This is actually a fine place to stop, for now, the next and
netxlite refactoring at https://github.com/ooni/probe/issues/2121.

internal/engine/experiment/ndt7/dial.go

@@ -30,7 +30,7 @@ func newDialManager(ndt7URL string, logger model.Logger, userAgent string) dialM
 }
 
 func (mgr dialManager) dialWithTestName(ctx context.Context, testName string) (*websocket.Conn, error) {
-	reso := netxlite.NewResolverStdlib(mgr.logger)
+	reso := netxlite.NewStdlibResolver(mgr.logger)
 	dlr := netxlite.NewDialerWithResolver(mgr.logger, reso)
 	dlr = bytecounter.WrapWithContextAwareDialer(dlr)
 	// Implements shaping if the user builds using `-tags shaping`

internal/engine/geolocate/geolocate.go

@@ -114,7 +114,7 @@ func NewTask(config Config) *Task {
 		config.UserAgent = fmt.Sprintf("ooniprobe-engine/%s", version.Version)
 	}
 	if config.Resolver == nil {
-		config.Resolver = netxlite.NewResolverStdlib(config.Logger)
+		config.Resolver = netxlite.NewStdlibResolver(config.Logger)
 	}
 	return &Task{
 		countryLookupper:     mmdbLookupper{},

internal/engine/geolocate/iplookup_test.go

@@ -14,7 +14,7 @@ import (
 func TestIPLookupGood(t *testing.T) {
 	ip, err := (ipLookupClient{
 		Logger:    log.Log,
-		Resolver:  netxlite.NewResolverStdlib(model.DiscardLogger),
+		Resolver:  netxlite.NewStdlibResolver(model.DiscardLogger),
 		UserAgent: "ooniprobe-engine/0.1.0",
 	}).LookupProbeIP(context.Background())
 	if err != nil {
@@ -30,7 +30,7 @@ func TestIPLookupAllFailed(t *testing.T) {
 	cancel() // immediately cancel to cause Do() to fail
 	ip, err := (ipLookupClient{
 		Logger:    log.Log,
-		Resolver:  netxlite.NewResolverStdlib(model.DiscardLogger),
+		Resolver:  netxlite.NewStdlibResolver(model.DiscardLogger),
 		UserAgent: "ooniprobe-engine/0.1.0",
 	}).LookupProbeIP(ctx)
 	if !errors.Is(err, context.Canceled) {
@@ -45,7 +45,7 @@ func TestIPLookupInvalidIP(t *testing.T) {
 	ctx := context.Background()
 	ip, err := (ipLookupClient{
 		Logger:    log.Log,
-		Resolver:  netxlite.NewResolverStdlib(model.DiscardLogger),
+		Resolver:  netxlite.NewStdlibResolver(model.DiscardLogger),
 		UserAgent: "ooniprobe-engine/0.1.0",
 	}).doWithCustomFunc(ctx, invalidIPLookup)
 	if !errors.Is(err, ErrInvalidIPAddress) {

internal/engine/netx/dnstransport.go

@@ -65,7 +65,7 @@ func NewDNSClientWithOverrides(config Config, URL, hostOverride, SNIOverride,
 	}
 	switch resolverURL.Scheme {
 	case "system":
-		return netxlite.NewResolverSystem(), nil
+		return netxlite.NewUnwrappedStdlibResolver(), nil
 	case "https":
 		config.TLSConfig.NextProtos = []string{"h2", "http/1.1"}
 		httpClient := &http.Client{Transport: NewHTTPTransport(config)}

internal/engine/netx/resolver.go

@@ -12,7 +12,7 @@ import (
 // NewResolver creates a new resolver from the specified config.
 func NewResolver(config Config) model.Resolver {
 	if config.BaseResolver == nil {
-		config.BaseResolver = netxlite.NewResolverSystem()
+		config.BaseResolver = netxlite.NewUnwrappedStdlibResolver()
 	}
 	r := netxlite.WrapResolver(
 		model.ValidLoggerOrDefault(config.Logger),