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/javaInterop/generics/invariantArgumentsNoWildcard.kt

@@ -0,0 +1,24 @@
+// TODO: muted automatically, investigate should it be ran for JS or not
+// IGNORE_BACKEND: JS
+
+// FILE: JavaClass.java
+
+public class JavaClass {
+    public static String test() {
+        return MainKt.bar(MainKt.foo());
+    }
+}
+
+// FILE: main.kt
+
+class Pair<out X, out Y>(val x: X, val y: Y)
+
+class Inv<T>(val x: T)
+
+fun foo(): Inv<Pair<CharSequence, CharSequence>> = Inv(Pair("O", "K"))
+
+fun bar(inv: Inv<Pair<CharSequence, CharSequence>>) = inv.x.x.toString() + inv.x.y
+
+fun box(): String {
+    return JavaClass.test();
+}