Drop unneeded synthetic package fragment construction from KotlinBuiltIns

Instead use package views of builtInsModule

idea/idea-completion/src/org/jetbrains/kotlin/idea/completion/AllClassesCompletion.kt

@@ -50,8 +50,8 @@ class AllClassesCompletion(private val parameters: CompletionParameters,
 
         //TODO: this is a temporary solution until we have built-ins in indices
         // we need only nested classes because top-level built-ins are all added through default imports
-        for (builtinPackage in resolutionFacade.moduleDescriptor.builtIns.builtInsPackageFragmentsImportedByDefault) {
-            collectClassesFromScope(builtinPackage.getMemberScope()) {
+        for (builtInPackage in resolutionFacade.moduleDescriptor.builtIns.builtInPackagesImportedByDefault) {
+            collectClassesFromScope(builtInPackage.memberScope) {
                 if (it.containingDeclaration is ClassDescriptor) {
                     classifierDescriptorCollector(it)
                 }