Move runtime js files down to lib/runtime/dart

lib/runtime/dart_utils.js

 // 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.
 
 /* This library defines a set of general javascript utilities for us
  * by the Dart runtime.
 */
 
 var dart_utils =
   typeof module != "undefined" && module.exports || {};
 
 (function (dart_utils) {
   'use strict';
 
   const defineProperty = Object.defineProperty;
   const getOwnPropertyDescriptor = Object.getOwnPropertyDescriptor;
   const getOwnPropertyNames = Object.getOwnPropertyNames;
   const getOwnPropertySymbols = Object.getOwnPropertySymbols;
 
   const hasOwnProperty = Object.prototype.hasOwnProperty;
 
-  const slice = [].slice;
-
   class StrongModeError extends Error {
     constructor(message) {
       super(message);
     }
   }
 
   /** This error indicates a strong mode specific failure.
    */
   function throwStrongModeError(message) {
     throw new StrongModeError(message);
@@ skipping 92 matching lines @@
     }
     if (hide != void 0) {
       var hideMap = new Set(hide);
       show = show.filter((k) => !hideMap.has(k));
     }
     return copyTheseProperties(to, from, show);
   }
   dart_utils.export = export_;
 
 })(dart_utils);