Generate singleton references as GET_OBJECT in nested classes

compiler/testData/ir/irText/expressions/enumEntryReferenceFromEnumEntryClass.kt

@@ -0,0 +1,28 @@
+enum class MyEnum {
+    Z {
+        var counter = 0
+        fun foo() {}
+
+        fun bar() {
+            counter = 1
+            foo()
+        }
+
+        val aLambda = {
+            counter = 1
+            foo()
+        }
+
+        val anObject = object {
+            init {
+                counter = 1
+                foo()
+            }
+
+            fun test() {
+                counter = 1
+                foo()
+            }
+        }
+    }
+}