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/reflection/properties/privateClassVal.kt

@@ -0,0 +1,33 @@
+// TODO: muted automatically, investigate should it be ran for JS or not
+// IGNORE_BACKEND: JS
+
+// WITH_REFLECT
+
+import kotlin.reflect.*
+import kotlin.reflect.jvm.isAccessible
+
+class Result {
+    private val value = "OK"
+
+    fun ref() = Result::class.memberProperties.single() as KProperty1<Result, String>
+}
+
+fun box(): String {
+    val p = Result().ref()
+    try {
+        p.get(Result())
+        return "Fail: private property is accessible by default"
+    } catch(e: IllegalCallableAccessException) { }
+
+    p.isAccessible = true
+
+    val r = p.get(Result())
+
+    p.isAccessible = false
+    try {
+        p.get(Result())
+        return "Fail: setAccessible(false) had no effect"
+    } catch(e: IllegalCallableAccessException) { }
+
+    return r
+}