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

compiler/testData/diagnostics/testsWithStdLib/annotations/platformStatic/functions.kt

@@ -2,7 +2,7 @@
 import kotlin.platform.platformStatic
 
 class A {
-    class object {
+    default object {
         platformStatic fun a1() {
 
         }
@@ -28,7 +28,7 @@ class A {
 }
 
 trait B {
-    class object {
+    default object {
         <!PLATFORM_STATIC_NOT_IN_OBJECT!>platformStatic fun a1()<!> {
 
         }

compiler/testData/diagnostics/testsWithStdLib/annotations/platformStatic/functions.txt

@@ -16,7 +16,7 @@ internal final class A {
         public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
     }
 
-    internal class object Default {
+    internal default object Default {
         private constructor Default()
         kotlin.platform.platformStatic() internal final fun a1(): kotlin.Unit
         public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
@@ -40,7 +40,7 @@ internal trait B {
         public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
     }
 
-    internal class object Default {
+    internal default object Default {
         private constructor Default()
         kotlin.platform.platformStatic() internal final fun a1(): kotlin.Unit
         public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean

compiler/testData/diagnostics/testsWithStdLib/annotations/platformStatic/property.kt

@@ -7,7 +7,7 @@ open class B {
 }
 
 class A {
-    class object : B() {
+    default object : B() {
         var p1:Int = 1
             [platformStatic] set(p: Int) {
                 p1 = 1

compiler/testData/diagnostics/testsWithStdLib/annotations/platformStatic/property.txt

@@ -20,7 +20,7 @@ internal final class A {
         public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
     }
 
-    internal class object Default : B {
+    internal default object Default : B {
         private constructor Default()
         kotlin.platform.platformStatic() public open override /*1*/ val base1: kotlin.Int = 0
         public open override /*1*/ val base2: kotlin.Int = 0