test: remove unnecessary skipIfWorker()

test-inspector-port-cluster passes in workers. Remove skipIfWorker()
from the test.

PR-URL: https://github.com/nodejs/node/pull/25427
Reviewed-By: Eugene Ostroukhov <eostroukhov@google.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>

test/sequential/test-inspector-port-cluster.js

@@ -3,7 +3,6 @@
 const common = require('../common');
 
 common.skipIfInspectorDisabled();
-common.skipIfWorker();
 
 const assert = require('assert');
 const cluster = require('cluster');