ipv6: re-enable tests on Dragonfly

Now that golang.org/x/net was re-vendored into std, these tests should
pass again.

Updates golang/go#34368

Change-Id: I6f253896836fb18d46875a9420de58ca05a49646
Reviewed-on: https://go-review.googlesource.com/c/net/+/202457
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

ipv6/multicastlistener_test.go

@@ -23,8 +23,6 @@ func TestUDPSinglePacketConnWithMultipleGroupListeners(t *testing.T) {
 	switch runtime.GOOS {
 	case "fuchsia", "hurd", "js", "nacl", "plan9", "windows":
 		t.Skipf("not supported on %s", runtime.GOOS)
-	case "dragonfly":
-		t.Skipf("skipping on %s until CL 202317 is vendored into std; see golang.org/issue/34368", runtime.GOOS)
 	}
 	if !nettest.SupportsIPv6() {
 		t.Skip("ipv6 is not supported")
@@ -65,8 +63,6 @@ func TestUDPMultiplePacketConnWithMultipleGroupListeners(t *testing.T) {
 	switch runtime.GOOS {
 	case "fuchsia", "hurd", "js", "nacl", "plan9", "windows":
 		t.Skipf("not supported on %s", runtime.GOOS)
-	case "dragonfly":
-		t.Skipf("skipping on %s until CL 202317 is vendored into std; see golang.org/issue/34368", runtime.GOOS)
 	}
 	if !nettest.SupportsIPv6() {
 		t.Skip("ipv6 is not supported")
@@ -122,8 +118,6 @@ func TestUDPPerInterfaceSinglePacketConnWithSingleGroupListener(t *testing.T) {
 	switch runtime.GOOS {
 	case "fuchsia", "hurd", "js", "nacl", "plan9", "windows":
 		t.Skipf("not supported on %s", runtime.GOOS)
-	case "dragonfly":
-		t.Skipf("skipping on %s until CL 202317 is vendored into std; see golang.org/issue/34368", runtime.GOOS)
 	}
 	if !nettest.SupportsIPv6() {
 		t.Skip("ipv6 is not supported")
@@ -180,8 +174,6 @@ func TestIPSinglePacketConnWithSingleGroupListener(t *testing.T) {
 	switch runtime.GOOS {
 	case "fuchsia", "hurd", "js", "nacl", "plan9", "windows":
 		t.Skipf("not supported on %s", runtime.GOOS)
-	case "dragonfly":
-		t.Skipf("skipping on %s until CL 202317 is vendored into std; see golang.org/issue/34368", runtime.GOOS)
 	}
 	if !nettest.SupportsIPv6() {
 		t.Skip("ipv6 is not supported")