Replace 'class object' with 'default object' in renderers and test data

Includes changes to decompiled text
Old syntax is used in builtins and project code for now

j2k/testData/fileOrElement/switch/comlicatedFallDown.kt

@@ -1,7 +1,7 @@
 package demo
 
 public class SwitchDemo {
-    class object {
+    default object {
         public fun print(o: Any) {
             System.out.println(o)
         }

j2k/testData/fileOrElement/switch/emptySwitch.kt

@@ -1,5 +1,5 @@
 public class NonDefault {
-    class object {
+    default object {
         public fun main(args: Array<String>) {
 
             val value = 3

j2k/testData/fileOrElement/switch/fallDown.kt

@@ -1,7 +1,7 @@
 package switch_demo
 
 public class SwitchDemo {
-    class object {
+    default object {
         public fun main(args: Array<String>) {
             val month = 8
             val monthString: String

j2k/testData/fileOrElement/switch/fallDownWithBlocks.kt

@@ -1,5 +1,5 @@
 public class C {
-    class object {
+    default object {
         public fun main(args: Array<String>) {
             when (args.size) {
                 1 -> {

j2k/testData/fileOrElement/switch/kt-539.kt

@@ -1,7 +1,7 @@
 package switch_demo
 
 public class SwitchDemo {
-    class object {
+    default object {
         public fun main(args: Array<String>) {
 
             val month = 8

j2k/testData/fileOrElement/switch/nondefault.kt

@@ -1,5 +1,5 @@
 public class NonDefault {
-    class object {
+    default object {
         public fun main(args: Array<String>) {
 
             val value = 3