Remove deprecated IllegalJSRegExpException class.

sdk/lib/core/exceptions.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.
 
 part of dart.core;
 
 // Exceptions are thrown either by the VM or from Dart code.
 
 /**
  * A marker interface implemented by all core library exceptions.
@@ skipping 35 matching lines @@
   final String message;
 
   /**
    * Creates a new FormatException with an optional error [message].
    */
   const FormatException([this.message = ""]);
 
   String toString() => "FormatException: $message";
 }
 
-/**
- * Deprecated. Replaced by [FormatException].
- */
-@deprecated
-class IllegalJSRegExpException extends FormatException {
-  IllegalJSRegExpException(String pattern, String errmsg)
-      : super("Illegal pattern: $pattern, $errmsg");
-}
-
-
 class IntegerDivisionByZeroException implements Exception {
   const IntegerDivisionByZeroException();
   String toString() => "IntegerDivisionByZeroException";
 }