benchmark: Correct constructor for freelist

Updates to use current constructor for freelist, which was changed
under pr #12644

Ref: #12644
PR-URL: #14627
Reviewed-By: Luigi Pinca <[email protected]>
Reviewed-By: James M Snell <[email protected]>
Reviewed-By: Gibson Fahnestock <[email protected]>
Reviewed-By: Colin Ihrig <[email protected]>
Reviewed-By: Anna Henningsen <[email protected]>

benchmark/misc/freelist.js

@@ -9,7 +9,7 @@ var bench = common.createBenchmark(main, {
 });
 
 function main(conf) {
-  const FreeList = require('internal/freelist').FreeList;
+  const FreeList = require('internal/freelist');
   var n = conf.n;
   var poolSize = 1000;
   var list = new FreeList('test', poolSize, Object);