Treat SEALED_SUBCLASS_FQ_NAME_LIST change as a class signature change

#KT-19580

jps-plugin/testData/comparison/classSignatureChange/sealedClassNestedImplAddedDeep/old.kt

@@ -0,0 +1,19 @@
+package test
+
+sealed class Base1 {
+    sealed class Nested1 : Base1() {
+        sealed class Nested2 : Nested1()
+    }
+}
+
+sealed class Base2 {
+    sealed class Nested1 : Base2() {
+        class Nested2 : Nested1()
+    }
+}
+
+sealed class Base3 {
+    sealed class Nested1 : Base3() {
+        class Nested2
+    }
+}