add tests for serializaion of nested classes and objects (builtins and js)

compiler/testData/serialization/builtinsSerializer/nestedClassesAndObjects.kt

@@ -0,0 +1,40 @@
+package test
+
+class ClassA {
+    class classB {
+        fun memberFromB(): Int = 100
+
+        class BC {
+            val memberFromBB: Int = 150
+        }
+
+        object BO {
+            val memberFromBO: Int = 175
+        }
+    }
+
+    inner class classC {
+        val memberFromC: Int = 200
+
+        class CC {
+            val memberFromCC: Int = 250
+        }
+
+        object CO {
+            val memberFromCO: Int = 265
+        }
+    }
+
+    companion object {
+        val stat: Int
+
+        class D {
+            val memberFromD: Int = 275
+        }
+    }
+
+    object ObjA {
+        val memberFromObjA: Int = 300
+    }
+}
+