Revert "Start moving the JavaScript backend related code into a separate library"

lib/compiler/implementation/js_backend/js_backend.dart

Index: lib/compiler/implementation/js_backend/js_backend.dart
diff --git a/lib/compiler/implementation/js_backend/js_backend.dart b/lib/compiler/implementation/js_backend/js_backend.dart
deleted file mode 100644
index e495570015dee265ad3c487bd0164dc235cd86ce..0000000000000000000000000000000000000000
--- a/lib/compiler/implementation/js_backend/js_backend.dart
+++ /dev/null
@@ -1,20 +0,0 @@
-// Copyright (c) 2012, 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('js_backend');
-
-#import('../../compiler.dart', prefix: 'api');
-#import('../elements/elements.dart');
-#import('../leg.dart');
-#import('../native_handler.dart', prefix: 'native');
-#import('../scanner/scannerlib.dart');
-#import('../source_file.dart');
-#import('../source_map_builder.dart');
-#import('../ssa/ssa.dart');
-#import('../tree/tree.dart');
-#import('../util/util.dart');
-
-#source('backend.dart');
-#source('emitter.dart');
-#source('native_emitter.dart');