Move blackBoxFile() testData to box/ directory

Delete all test methods (and empty test classes), since they'll be
auto-generated

compiler/testData/codegen/box/functions/kt1199.kt

@@ -0,0 +1,21 @@
+fun <T : Any> T?.iterator() = object {
+    var hasNext = this@iterator != null
+      private set
+    fun hasNext() = hasNext
+
+    fun next() : T {
+        if (hasNext) {
+            hasNext = false
+            return this@iterator!!
+        }
+        throw java.util.NoSuchElementException()
+    }
+}
+
+fun box() : String {
+  var k = 0
+  for (i in 1) {
+    k++
+  }
+  return if(k == 1) "OK" else "fail"
+}