dart2js: Rename emitters.

pkg/compiler/lib/src/js_emitter/lazy_emitter/emitter.dart

 // Copyright (c) 2014, 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.
 
 library dart2js.new_js_emitter.emitter;
 
 import 'package:js_runtime/shared/embedded_names.dart' show
     JsBuiltin,
     METADATA,
     TYPES;
@@ skipping 164 matching lines @@
         _compiler.internalError(NO_LOCATION_SPANNABLE,
                                 "Unhandled Builtin: $builtin");
         return null;
     }
   }
 
   @override
   void invalidateCaches() {
   }
 }