Move core and coreimpl from corelib/ to lib/core and lib/coreimpl.

corelib/src/implementation/regexp.dart

Index: corelib/src/implementation/regexp.dart
diff --git a/corelib/src/implementation/regexp.dart b/corelib/src/implementation/regexp.dart
deleted file mode 100644
index ec20e72c0f53245d2476df8af9bb12fad926f7c9..0000000000000000000000000000000000000000
--- a/corelib/src/implementation/regexp.dart
+++ /dev/null
@@ -1,15 +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.
-
-class JSSyntaxRegExp implements RegExp {
-  external const JSSyntaxRegExp(String pattern,
-                                [bool multiLine, bool ignoreCase]);
-  external Match firstMatch(String str);
-  external Iterable<Match> allMatches(String str);
-  external bool hasMatch(String str);
-  external String stringMatch(String str);
-  external String get pattern();
-  external bool get multiLine();
-  external bool get ignoreCase();
-}