Test for obsolete KT-9642

#KT-9642 Obsolete

compiler/testData/codegen/box/classes/kt9642.kt

@@ -0,0 +1,17 @@
+class Outer {
+    class Nested {
+        fun fn(): String  {
+            s = "OK"
+            return s
+        }
+    }
+
+    companion object {
+        public var s = "fail"
+            private set
+    }
+}
+
+fun box(): String {
+    return Outer.Nested().fn()
+}