lib: wrap tick_processor scripts in IIFE

PR-URL: https://github.com/nodejs/node/pull/4722
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Michaël Zasso <mic.besace@gmail.com>

lib/internal/v8_prof_processor.js

@@ -25,5 +25,8 @@ if (process.platform === 'darwin') {
   tickArguments.push('--windows');
 }
 tickArguments.push.apply(tickArguments, process.argv.slice(1));
-script = 'arguments = ' + JSON.stringify(tickArguments) + ';\n' + script;
+script = `(function() {
+  arguments = ${JSON.stringify(tickArguments)};
+  ${script}
+})()`;
 eval(script);