benchmark: fix variables not being set

Due to the destructuring the outer variables were not set anymore.

PR-URL: nodejs#18320
Reviewed-By: James M Snell <[email protected]>

Author: BridgeAR

benchmark/tls/tls-connect.js

@@ -11,7 +11,6 @@ const bench = common.createBenchmark(main, {
 
 var clientConn = 0;
 var serverConn = 0;
-var server;
 var dur;
 var concurrency;
 var running = true;
@@ -28,7 +27,7 @@ function main(conf) {
     ciphers: 'AES256-GCM-SHA384'
   };
 
-  server = tls.createServer(options, onConnection);
+  const server = tls.createServer(options, onConnection);
   server.listen(common.PORT, onListening);
 }