Get rid of 'class object' usages in code and builtins

Replace some comments and library usages as well

compiler/light-classes/src/org/jetbrains/kotlin/asJava/KotlinCodeBlockModificationListener.kt

@@ -87,7 +87,7 @@ public class KotlinCodeBlockModificationListener(modificationTracker: PsiModific
         }
     }
 
-    class object {
+    companion object {
         private val LOG = Logger.getInstance("#org.jetbrains.kotlin.asJava.JetCodeBlockModificationListener")
 
         private fun containsClassesInside(element: PsiElement?): Boolean {

compiler/light-classes/src/org/jetbrains/kotlin/asJava/KotlinLightClassForPackage.kt

@@ -65,7 +65,7 @@ public class KotlinLightClassForPackage private(
             }
         }
 
-        class object {
+        companion object {
             public fun getInstance(project: Project): FileStubCache {
                 return ServiceManager.getService<FileStubCache>(project, javaClass<FileStubCache>())
             }
@@ -214,7 +214,7 @@ public class KotlinLightClassForPackage private(
         }
     }
 
-    class object Factory {
+    companion object Factory {
         public fun create(
                 manager: PsiManager,
                 qualifiedName: FqName,