Test for KT-9712 (fixed along with KT-9717)

#KT-9712 Fixed

compiler/testData/codegen/boxWithStdlib/delegatedProperty/kt9712.kt

@@ -0,0 +1,22 @@
+import kotlin.properties.Delegates
+
+object X {
+    public var O: String
+        by Delegates.observable("O") { prop, old, new -> }
+        private set
+}
+
+open class A {
+    public var K: String
+        by Delegates.observable("") { prop, old, new -> }
+        protected set
+}
+
+class B : A() {
+    init {
+        K = "K"
+    }
+}
+
+fun box(): String =
+        X.O + B().K