test: Replaced forEach with for..of in test-net-isipv6.js

Author: niyashiyas

test/parallel/test-net-isipv6.js

@@ -235,10 +235,10 @@ const v6not = [
   '02001:0000:1234:0000:0000:C1C0:ABCD:0876',
 ];
 
-v6.forEach((ip) => {
+for(const ip of v6) {
   assert.strictEqual(net.isIPv6(ip), true);
-});
+};
 
-v6not.forEach((ip) => {
+for(const ip of v6not) {
   assert.strictEqual(net.isIPv6(ip), false);
-});
+};