Refactor: process mentions of class object

Rename usages that refer to "default object" concept now
Test data file names are left as is

compiler/testData/diagnostics/tests/classObjects/InnerClassAccessThroughClassObject.kt

@@ -28,7 +28,7 @@ object O {
 fun f() {
     A.c
     A.hashCode()
-    A().<!NO_CLASS_OBJECT, NESTED_CLASS_ACCESSED_VIA_INSTANCE_REFERENCE!>Nested<!>
+    A().<!NO_DEFAULT_OBJECT, NESTED_CLASS_ACCESSED_VIA_INSTANCE_REFERENCE!>Nested<!>
     A.Nested()
     A().Inner()
     A.Default.<!UNRESOLVED_REFERENCE!>Nested<!>