Move native and js interop properties from the element model to the JS backend

pkg/compiler/lib/src/library_loader.dart

Index: pkg/compiler/lib/src/library_loader.dart
diff --git a/pkg/compiler/lib/src/library_loader.dart b/pkg/compiler/lib/src/library_loader.dart
index 5759b52e230bea6d22742a1548fb7e7014b7991c..f500f98dec7eb4c46390f37ad027972f4ff0f75a 100644
--- a/pkg/compiler/lib/src/library_loader.dart
+++ b/pkg/compiler/lib/src/library_loader.dart
@@ -31,7 +31,6 @@ import 'elements/modelx.dart' show
     PrefixElementX,
     SyntheticImportElement;
 
-import 'native/native.dart' as native;
 import 'script.dart';
 import 'tree/tree.dart';
 import 'util/util.dart' show
@@ -631,7 +630,6 @@ class _LibraryLoaderTask extends CompilerTask implements LibraryLoaderTask {
         handler.registerNewLibrary(element);
         libraryCanonicalUriMap[resolvedUri] = element;
       }
-      native.maybeEnableNative(compiler, element);
       compiler.scanner.scanLibrary(element);
       return element;
     });