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/dataClasses/hashCode/array.kt

@@ -0,0 +1,9 @@
+// TODO: muted automatically, investigate should it be ran for JS or not
+// IGNORE_BACKEND: JS
+
+data class A(val a: IntArray, var b: Array<String>)
+
+fun box() : String {
+   if( A(intArrayOf(1,2,3),arrayOf("239")).hashCode() != 31*java.util.Arrays.hashCode(intArrayOf(0,1,2)) + "239".hashCode()) "fail"
+   return "OK"
+}