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

Replace some comments and library usages as well

idea/ide-common/src/org/jetbrains/kotlin/idea/codeInsight/ReferenceVariantsHelper.kt

@@ -48,7 +48,7 @@ public class ReferenceVariantsHelper(
             public val receivers: Collection<ReceiverValue>,
             public val callType: CallType
     ) {
-        class object {
+        companion object {
             val Empty = ReceiversData(listOf(), CallType.NORMAL)
         }
     }
@@ -216,7 +216,7 @@ public class ReferenceVariantsHelper(
         return resolutionScope.getDescriptorsFiltered(DescriptorKindFilter.PACKAGES, nameFilter).filter(visibilityFilter)
     }
 
-    class object {
+    companion object {
         public fun getExplicitReceiverData(expression: JetSimpleNameExpression): Pair<JetExpression, CallType>? {
             val receiverExpression = expression.getReceiverExpression() ?: return null
             val parent = expression.getParent()

idea/ide-common/src/org/jetbrains/kotlin/resolve/lazy/PartialBodyResolveFilter.kt

@@ -469,7 +469,7 @@ class PartialBodyResolveFilter(
         NEED_COMPLETION
     }
 
-    class object {
+    companion object {
         private fun JetElement.blocks(): Collection<JetBlockExpression> {
             val result = ArrayList<JetBlockExpression>(1)
             this.accept(object : JetVisitorVoid() {