perf: 字符串 length 站点指针快判免 IC 读

tests/stress/string_length.js

@@ -0,0 +1,13 @@
+var ITERATIONS = 3000;
+
+var arr = [];
+for (var i = 0; i < 100; i++) {
+  arr.push("item" + i);
+}
+var sum = 0;
+for (var j = 0; j < ITERATIONS; j++) {
+  for (var k = 0; k < 100; k++) {
+    sum += arr[k].length;
+  }
+}
+sum