Generate enum entries classes with package private visibility

#KT-6574 Fixed

compiler/testData/writeFlags/class/visibility/packageprivate/enumEntry.kt

@@ -0,0 +1,9 @@
+enum class Foo {
+    A {
+        fun foo() {}
+    }
+}
+
+// TESTED_OBJECT_KIND: class
+// TESTED_OBJECTS: Foo$A
+// FLAGS: ACC_FINAL, ACC_SUPER