Introduce kotlin.Cloneable

- Cloneable is a trait with a single protected member 'clone', which is mapped
  to java.lang.Cloneable on JVM
- 'clone' is non-abstract to be able to call 'super.clone()' in the
  implementations. Also if you need your class to be Cloneable, most of the
  time inheriting from Cloneable and calling 'super.clone()' will work
- hack 'super.clone()' in JVM intrinsics and TImpl delegation generation
- make arrays Cloneable, handle 'clone()' calls in the intrinsic

 #KT-4890 Fixed

compiler/testData/codegen/box/javaInterop/objectMethods/cloneHashSet.kt

@@ -0,0 +1,12 @@
+import java.util.HashSet
+
+fun box(): String {
+    val a = HashSet<String>()
+    a.add("live")
+    a.add("long")
+    a.add("prosper")
+    val b = a.clone()
+    if (a != b) return "Fail equals"
+    if (a identityEquals b) return "Fail identity"
+    return "OK"
+}