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

PR-URL: #49823
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>

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);
-});
+}