fix `dynamic` type literal

lib/src/codegen/js_module_item_order.dart

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 import 'dart:collection' show HashMap;
 import 'package:analyzer/src/generated/ast.dart';
 import 'package:analyzer/src/generated/element.dart';
 import 'package:dev_compiler/src/compiler.dart' show corelibOrder;
 
 typedef void ModuleItemEmitter(AstNode item);
@@ skipping 162 matching lines @@
     for (var current in _topLevelElements) {
       // TODO(jmesserly): if we want to log what triggered laziness, this is
       // the place to do so.
       _loaded[current] = false;
     }
   }
 
   bool libraryIsLoaded(LibraryElement library) {
     assert(library != _currentLibrary);
 
+    // DynamicElementImpl has no library.
+    if (library == null) return true;
+
     // The SDK is a special case: we optimize the order to prevent laziness.
     if (_isDartUri(library)) {
       // SDK is loaded before non-SDK libraries
       if (!_isDartUri(_currentLibrary)) return true;
 
       // Compute the order of both SDK libraries. If unknown, assume it's after.
       var order = corelibOrder.indexOf(library.name);
       if (order == -1) order = corelibOrder.length;
 
       var currentOrder = corelibOrder.indexOf(_currentLibrary.name);
@@ skipping 32 matching lines @@
     }
     return _libraryCycleMemo[library] = result;
   }
 
   /// Returns whether this is a library imported with 'dart:' URI.
   ///
   /// This is similar to [LibraryElement.isInSdk], but checking the URI instead
   /// of the library naming convention, because the URI is reliable.
   static bool _isDartUri(LibraryElement e) => e.source.uri.scheme == 'dart';
 }