Move JSSyntaxRegExp to core as a private member. This removes the last refrences to dart:coreimpl.

sdk/lib/html/dart2js/html_dart2js.dart

 library html;
 
 import 'dart:isolate';
 import 'dart:json';
 import 'dart:svg' as svg;
 // 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.
 
 // DO NOT EDIT
@@ skipping 13629 matching lines @@
 
   /** @domName NodeIterator.previousNode */
   Node previousNode() native;
 }
 // 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.
 
 
 // TODO(nweiz): when all implementations we target have the same name for the
-// coreimpl implementation of List<E>, extend that rather than wrapping.
+// implementation of List<E>, extend that rather than wrapping.
 class _ListWrapper<E> implements List<E> {
   List _list;
 
   _ListWrapper(List this._list);
 
   Iterator<E> iterator() => _list.iterator();
 
   bool contains(E element) => _list.contains(element);
 
   void forEach(void f(E element)) => _list.forEach(f);
@@ skipping 11183 matching lines @@
     if (length < 0) throw new ArgumentError('length');
     if (start < 0) throw new RangeError.value(start);
     int end = start + length;
     if (end > a.length) throw new RangeError.value(end);
     for (int i = start; i < end; i++) {
       accumulator.add(a[i]);
     }
     return accumulator;
   }
 }