benchmark: change the execution order

This changes the execution order from "iter, file, binary" to "file,
iter, binary". This means the csv no longer has to buffered completely.

This also has the added effect that stopping compare.js early or
interfering with performance only affects a single benchmark, instead of
all of them.

Refs: https://github.com/nodejs/node/issues/8659
PR-URL: https://github.com/nodejs/node/pull/9064
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Brian White <mscdex@mscdex.net>

benchmark/compare.js

@@ -40,8 +40,8 @@ if (benchmarks.length === 0) {
 // Create queue from the benchmarks list such both node versions are tested
 // `runs` amount of times each.
 const queue = [];
-for (let iter = 0; iter < runs; iter++) {
-  for (const filename of benchmarks) {
+for (const filename of benchmarks) {
+  for (let iter = 0; iter < runs; iter++) {
     for (const binary of binaries) {
       queue.push({ binary, filename, iter });
     }