Fix type of reference to protected var

#KT-12982 Fixed

compiler/testData/codegen/box/callableReference/property/kt12982_protectedPropertyReference.kt

@@ -0,0 +1,12 @@
+class Foo {
+    protected var x = 0
+
+    fun getX() = Foo::x
+}
+
+fun box(): String {
+    val x = Foo().getX()
+    val foo = Foo()
+    x.set(foo, 42)
+    return if (x.get(foo) == 42) "OK" else "Fail"
+}