util/linuxfw,go.{mod,sum}: don't log errors when deleting non-existant chains and rules (#11852)

This PR bumps iptables to a newer version that has a function to detect
'NotExists' errors and uses that function to determine whether errors
received on iptables rule and chain clean up are because the rule/chain
does not exist- if so don't log the error.

Updates corp#19336

Signed-off-by: Irbe Krumina <irbe@tailscale.com>

util/linuxfw/iptables_runner_test.go

@@ -13,6 +13,12 @@ import (
 	"tailscale.com/net/tsaddr"
 )
 
+var testIsNotExistErr = "exitcode:1"
+
+func init() {
+	isNotExistError = func(e error) bool { return e.Error() == testIsNotExistErr }
+}
+
 func TestAddAndDeleteChains(t *testing.T) {
 	iptr := NewFakeIPTablesRunner()
 	err := iptr.AddChains()