Fix EsLint Brackets (error markup 'const').

node_modules/functional-red-black-tree/bench/test.js

@@ -0,0 +1,11 @@
+"use strict"
+
+var createTree = require("../rbtree.js")
+
+var t = createTree()
+
+var s = Date.now()
+for(var i=0; i<100000; ++i) {
+  t = t.insert(Math.random(), Math.random())
+}
+console.log(Date.now() - s)