JS: create new common directory for all generated tests, migrate several tests there

js/js.translator/testData/box/closure/iteratingCallbacks.kt

@@ -0,0 +1,29 @@
+package foo
+
+import java.util.*
+
+fun box(): String {
+    val oneTwo = Array(2) {
+        it + 1
+    }
+    val a = ArrayList<() -> Int>()
+    for (i in oneTwo) {
+        for (j in 1..2) {
+            a.add({
+                      var res = 0
+                      for (t in 0..2) {
+                          res += i * j
+                      }
+                      res
+                  })
+        }
+    }
+    var sum = 0
+    for (f in a) {
+        sum += f()
+    }
+
+    if (sum != 27) return "fail: $sum"
+
+    return "OK"
+}