Delete dart2js specific private library code

tool/input_sdk/private/interceptors.dart

 // 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 _interceptors;
 
 import 'dart:_js_embedded_names' show
     DISPATCH_PROPERTY_NAME,
     MAP_TYPE_TO_INTERCEPTOR;
 
@@ skipping 13 matching lines @@
                               initNativeDispatch,
                               initNativeDispatchFlag,
                               regExpGetNative,
                               regExpCaptureCount,
                               stringContainsUnchecked,
                               stringLastIndexOfUnchecked,
                               stringReplaceAllFuncUnchecked,
                               stringReplaceAllUnchecked,
                               stringReplaceFirstUnchecked,
                               lookupAndCacheInterceptor,
-                              lookupDispatchRecord,
                               StringMatch,
                               firstMatchAfter,
                               NoInline;
 import 'dart:_foreign_helper' show
     JS,
     JS_EFFECT,
     JS_EMBEDDED_GLOBAL,
     JS_INTERCEPTOR_CONSTANT,
     JS_STRING_CONCAT;
 import 'dart:math' show Random;
@@ skipping 352 matching lines @@
  * Interceptor for unclassified JavaScript objects, typically objects with a
  * non-trivial prototype chain.
  *
  * This class also serves as a fallback for unknown JavaScript exceptions.
  */
 class UnknownJavaScriptObject extends JavaScriptObject {
   const UnknownJavaScriptObject();
 
   String toString() => JS('String', 'String(#)', this);
 }