moved benchmark lox files to separate folder

lox.t/benchmark/trees.lox

@@ -1,29 +0,0 @@
-class Tree {
-  init(depth) {
-    this.depth = depth;
-    if (depth > 0) {
-      this.a = Tree(depth - 1);
-      this.b = Tree(depth - 1);
-      this.c = Tree(depth - 1);
-      this.d = Tree(depth - 1);
-      this.e = Tree(depth - 1);
-    }
-  }
-
-  walk() {
-    if (this.depth == 0) return 0;
-    return this.depth 
-        + this.a.walk()
-        + this.b.walk()
-        + this.c.walk()
-        + this.d.walk()
-        + this.e.walk();
-  }
-}
-
-var tree = Tree(8);
-var start = clock();
-for (var i = 0; i < 100; i = i + 1) {
-  if (tree.walk() != 122068) print "Error";
-}
-print clock() - start;