test: show values instead of assertion message

PR-URL: nodejs/node#15979
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>

Author: dinophile

test/internet/test-dgram-multicast-multi-process.js

@@ -111,8 +111,7 @@ function launchChildProcess() {
           console.error('[PARENT] %d received %d matching messages.',
                         worker.pid, count);
 
-          assert.strictEqual(count, messages.length,
-                             'A worker received an invalid multicast message');
+          assert.strictEqual(count, messages.length);
         });
 
         clearTimeout(timer);