More fixes.

runtime/bin/builtin.dart

Index: runtime/bin/builtin.dart
diff --git a/runtime/bin/builtin.dart b/runtime/bin/builtin.dart
index 7780208d68dd0da2a16f17e82e38c6848460f801..d4aa012467d9c3d2bf6f182116421de5f3381ae4 100644
--- a/runtime/bin/builtin.dart
+++ b/runtime/bin/builtin.dart
@@ -346,11 +346,11 @@ _setupHooks() {
 // Handling of Resource class by dispatching to the load port.
 Future<List<int>> _resourceReadAsBytes(Uri uri) async {
   List response = await _makeLoaderRequest(_Dart_kResourceLoad, uri.toString());
-  if (response[3] is String) {
+  if (response[4] is String) {
     // Throw the error.
-    throw response[3];
+    throw response[4];
   } else {
-    return response[3];
+    return response[4];
   }
 }