backend/tests: Add blackbox tests from Kotlin JVM

Added tests from testData/codegen/box directory. There are blackbox tests
in other directories and they are to be added.

backend.native/tests/external/codegen/blackbox/controlStructures/emptyFor.kt

@@ -0,0 +1,19 @@
+var index = 0
+
+interface IterableIterator : Iterator<Int> {
+    operator fun iterator(): Iterator<Int> = this
+}
+
+val iterator = object : IterableIterator {
+    override fun hasNext() = index < 5
+    override fun next() = index++
+}
+
+fun box(): String {
+    for (x in 1..5);
+
+    for (x in iterator);
+    if (index != 5) return "Fail: $index"
+
+    return "OK"
+}