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/builtinStubMethods/Iterator.kt

@@ -0,0 +1,16 @@
+// TODO: muted automatically, investigate should it be ran for JS or not
+// IGNORE_BACKEND: JS
+
+class MyIterator<T>(val v: T): Iterator<T> {
+    override fun next(): T = v
+    override fun hasNext(): Boolean = true
+}
+
+fun box(): String {
+    try {
+        (MyIterator<String>("") as java.util.Iterator<String>).remove()
+        throw AssertionError()
+    } catch (e: UnsupportedOperationException) {
+        return "OK"
+    }
+}