test: remove message argument in cluster setup test

In test/parallel/test-cluster-setup-master-cumulative.js:

Remove the message parameter to ensure that the compared
objects are printed out. Add the original message as a
comment above.

PR-URL: nodejs#16838
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>

test/parallel/test-cluster-setup-master-cumulative.js

@@ -26,11 +26,8 @@ const cluster = require('cluster');
 
 assert(cluster.isMaster);
 
-assert.deepStrictEqual(
-  cluster.settings,
-  {},
-  'cluster.settings should not be initialized until needed'
-);
+// cluster.settings should not be initialized until needed
+assert.deepStrictEqual(cluster.settings, {});
 
 cluster.setupMaster();
 assert.deepStrictEqual(cluster.settings, {