test: skip test-v8-serialize-leak on IBM i

On IBM i rss memory information is not available and always returns `0`.

PR-URL: nodejs#43511
Refs: nodejs#43509
Refs: libuv/libuv#2732
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>

test/parallel/test-v8-serialize-leak.js

@@ -1,7 +1,12 @@
 'use strict';
 // Flags: --expose-gc
 
-require('../common');
+const common = require('../common');
+
+// On IBMi, the rss memory always returns zero
+if (common.isIBMi)
+  common.skip('On IBMi, the rss memory always returns zero');
+
 const v8 = require('v8');
 const assert = require('assert');