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

Replace some comments and library usages as well

js/js.dart-ast/src/com/google/dart/compiler/backend/js/ast/jsScopes.kt

@@ -80,7 +80,7 @@ public open class JsFunctionScope(parent: JsScope, description: String) : JsScop
                 || getParent()?.hasOwnName(name) ?: false
     }
 
-    class object {
+    companion object {
         public val RESERVED_WORDS: Set<String> = setOf(
                 // keywords
                 "await", "break", "case", "catch", "continue", "debugger", "default", "delete", "do", "else", "finally", "for", "function", "if",

js/js.frontend/src/org/jetbrains/kotlin/js/PredefinedAnnotation.kt

@@ -28,7 +28,7 @@ public enum class PredefinedAnnotation(fqName: String) {
 
     public val fqName: FqName = FqName(fqName)
 
-    class object {
+    companion object {
         // TODO: replace with straight assignment when KT-5761 will be fixed
         val WITH_CUSTOM_NAME by Delegates.lazy { setOf(LIBRARY, NATIVE) }
     }

js/js.frontend/src/org/jetbrains/kotlin/js/analyzer/JsAnalysisResult.kt

@@ -28,7 +28,7 @@ public class JsAnalysisResult(
         moduleDescriptor: ModuleDescriptor
 ) : AnalysisResult(bindingTrace.getBindingContext(), moduleDescriptor) {
 
-    class object {
+    companion object {
         platformStatic public fun success(trace: BindingTrace, module: ModuleDescriptor): JsAnalysisResult {
             return JsAnalysisResult(trace, module)
         }

js/js.frontend/src/org/jetbrains/kotlin/js/resolve/diagnostics/JsCallChecker.kt

@@ -54,7 +54,7 @@ import org.jetbrains.kotlin.resolve.TemporaryBindingTrace
 
 public class JsCallChecker : CallChecker {
 
-    class object {
+    companion object {
         private val JS_PATTERN: DescriptorPredicate = PatternBuilder.pattern("kotlin.js.js(String)")
 
         platformStatic

js/js.libraries/src/core/dom.kt

@@ -93,7 +93,7 @@ native public trait DOMError {
     public val severity: Short
     public val type: String
 
-    public class object {
+    public companion object {
         public val SEVERITY_ERROR: Short = 2
         public val SEVERITY_FATAL_ERROR: Short = 3
         public val SEVERITY_WARNING: Short = 1
@@ -221,7 +221,7 @@ native public trait Node {
     public fun replaceChild(arg1: Node, arg2: Node): Node = noImpl
     public fun setUserData(arg1: String?, arg2: Any, arg3: UserDataHandler): Any = noImpl
 
-    public class object {
+    public companion object {
         public val ATTRIBUTE_NODE: Short = 2
         public val CDATA_SECTION_NODE: Short = 4
         public val COMMENT_NODE: Short = 8
@@ -270,7 +270,7 @@ native public trait TypeInfo {
     public val typeNamespace: String
     public fun isDerivedFrom(arg1: String?, arg2: String?, arg3: Int): Boolean = noImpl
 
-    public class object {
+    public companion object {
         public val DERIVATION_EXTENSION: Int = 2
         public val DERIVATION_LIST: Int = 8
         public val DERIVATION_RESTRICTION: Int = 1
@@ -281,7 +281,7 @@ native public trait TypeInfo {
 native public trait UserDataHandler {
     public fun handle(arg1: Short, arg2: String?, arg3: Any, arg4: Node, arg5: Node): Unit = noImpl
 
-    public class object {
+    public companion object {
         public val NODE_ADOPTED: Short = 5
         public val NODE_CLONED: Short = 1
         public val NODE_DELETED: Short = 3

js/js.libraries/src/core/domEvents.kt

@@ -29,7 +29,7 @@ native public trait Event {
     public fun preventDefault(): Unit = noImpl
     public fun stopPropagation(): Unit = noImpl
 
-    public class object {
+    public companion object {
         public val AT_TARGET: Short = 2
         public val BUBBLING_PHASE: Short = 3
         public val CAPTURING_PHASE: Short = 1
@@ -64,7 +64,7 @@ native public trait MutationEvent: Event {
     public val relatedNode: Node
     public fun initMutationEvent(arg1: String?, arg2: Boolean, arg3: Boolean, arg4: Node, arg5: String?, arg6: String?, arg7: String?, arg8: Short): Unit = noImpl
 
-    public class object {
+    public companion object {
         public val ADDITION: Short = 2
         public val MODIFICATION: Short = 1
         public val REMOVAL: Short = 3

js/js.translator/testData/delegation/cases/onObject.kt

@@ -9,7 +9,7 @@ class TImpl(val v: String) : T {
 }
 
 class A {
-    class object : T by TImpl("A.Default")
+    companion object : T by TImpl("A.Default")
 }
 
 object B : T by TImpl("B")