all: use Go 1.22 range-over-int

Updates #11058

Change-Id: I35e7ef9b90e83cac04ca93fd964ad00ed5b48430
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>

net/portmapper/portmapper_test.go

@@ -21,7 +21,7 @@ func TestCreateOrGetMapping(t *testing.T) {
 	c := NewClient(t.Logf, nil, nil, new(controlknobs.Knobs), nil)
 	defer c.Close()
 	c.SetLocalPort(1234)
-	for i := 0; i < 2; i++ {
+	for i := range 2 {
 		if i > 0 {
 			time.Sleep(100 * time.Millisecond)
 		}
@@ -36,7 +36,7 @@ func TestClientProbe(t *testing.T) {
 	}
 	c := NewClient(t.Logf, nil, nil, new(controlknobs.Knobs), nil)
 	defer c.Close()
-	for i := 0; i < 3; i++ {
+	for i := range 3 {
 		if i > 0 {
 			time.Sleep(100 * time.Millisecond)
 		}

net/portmapper/upnp_test.go

@@ -597,7 +597,7 @@ func TestGetUPnPPortMapping(t *testing.T) {
 			firstResponse netip.AddrPort
 			prevPort      uint16
 		)
-		for i := 0; i < 2; i++ {
+		for i := range 2 {
 			sawRequestWithLease.Store(false)
 			res, err := c.Probe(ctx)
 			if err != nil {