test: add mustCall for parallel/test-net-connect-paused-connection

Add common.mustCall test on net.createServer callback and listen
callback in the parallel/test-net-connect-paused-connection

remove the mustCall of net.createServer callback

PR-URL: #27463
Reviewed-By: Yongsheng Zhang <zyszys98@gmail.com>
Reviewed-By: Weijia Wang <starkwang@126.com>
Reviewed-By: Yorkie Liu <yorkiefixer@gmail.com>
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Ouyang Yadong <oyydoibh@gmail.com>

Author: sujunfei

test/parallel/test-net-connect-paused-connection.js

@@ -26,8 +26,8 @@ const net = require('net');
 
 net.createServer(function(conn) {
   conn.unref();
-}).listen(0, function() {
+}).listen(0, common.mustCall(function() {
   net.connect(this.address().port, 'localhost').pause();
 
   setTimeout(common.mustNotCall('expected to exit'), 1000).unref();
-}).unref();
+})).unref();