Fix private setter visibility for generic class

#KT-8888 fixed

compiler/testData/diagnostics/tests/scopes/invisibleSetter.kt

@@ -0,0 +1,9 @@
+class A<T> {
+    public var x: Int = 0
+        private set
+}
+
+fun main(args: Array<String>) {
+    val a = A<Any>()
+    <!INVISIBLE_SETTER!>a.x<!> = 1
+}