test: fix test-net-pingpong pummel test for non-IPv6 hosts

Use `common.hasIPv6` instead of an OS check for more reliable
operation.

PR-URL: #34359
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>

test/pummel/test-net-pingpong.js

@@ -113,9 +113,8 @@ function pingPongTest(host, on_complete) {
 pingPongTest('localhost');
 pingPongTest(null);
 
-// This IPv6 isn't working on Solaris.
-if (!common.isSunOS) pingPongTest('::1');
+if (common.hasIPv6) pingPongTest('::1');
 
 process.on('exit', function() {
-  assert.strictEqual(tests_run, common.isSunOS ? 2 : 3);
+  assert.strictEqual(tests_run, common.hasIPv6 ? 3 : 2);
 });