fixes

benchmarks/binarytree.ce

@@ -7,7 +7,7 @@ function mainThread() {
 
   var longLivedTree = bottomUpTree(maxDepth);
 
-  for (let depth = 4; depth <= maxDepth; depth += 2) {
+  for (var depth = 4; depth <= maxDepth; depth += 2) {
     var iterations = 1 << maxDepth - depth + 4;
     work(iterations, depth);
   }
@@ -16,8 +16,8 @@ function mainThread() {
 }
 
 function work(iterations, depth) {
-  let check = 0;
-  for (let i = 0; i < iterations; i++)
+  var check = 0;
+  for (var i = 0; i < iterations; i++)
     check += itemCheck(bottomUpTree(depth));
   log.console(`${iterations}\t trees of depth ${depth}\t check: ${check}`);
 }