benchmark: use strict mode

Apply strict mode to benchmark code.

PR-URL: https://github.com/nodejs/node/pull/5336
Reviewed-By: James M Snell <[email protected]>
Reviewed-By: Jeremiah Senkpiel <[email protected]>
Reviewed-By: Roman Reiss <[email protected]>
Reviewed-By: Ben Noordhuis <[email protected]>
diff --git a/benchmark/net/tcp-raw-c2s.js b/benchmark/net/tcp-raw-c2s.js
index 0039313..25efc78 100644
--- a/benchmark/net/tcp-raw-c2s.js
+++ b/benchmark/net/tcp-raw-c2s.js
@@ -1,5 +1,6 @@
 // In this benchmark, we connect a client to the server, and write
 // as many bytes as we can in the specified time (default = 10s)
+'use strict';
 
 var common = require('../common.js');
 var util = require('util');