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/objects/objectLiteralInClosure.kt

@@ -0,0 +1,17 @@
+package p
+
+private class C(val y: Int) {
+    val initChild = { ->
+        object {
+            override fun toString(): String {
+                return "child" + y
+            }
+        }
+    }
+}
+
+fun box(): String {
+    val c = C(3).initChild
+    val x = c().toString()
+    return if (x == "child3") "OK" else x
+}