unittest fix: Get rid of the deprecation of IllegalJsRegexException's matcher.

pkg/unittest/lib/src/core_matchers.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 matcher;
 
 /**
  * Returns a matcher that matches empty strings, maps or iterables
  * (including collections).
  */
@@ skipping 465 matching lines @@
 
 /** A matcher for functions that throw ArgumentError. */
 const Matcher throwsArgumentError =
     const Throws(isArgumentError);
 
 class _ArgumentError extends TypeMatcher {
   const _ArgumentError() : super("ArgumentError");
   bool matches(item, MatchState matchState) => item is ArgumentError;
 }
 
-/** A matcher for IllegalJSRegExpExceptions. */
-const isIllegalJSRegExpException = const _IllegalJSRegExpException();
-
-/** A matcher for functions that throw IllegalJSRegExpException. */
-@deprecated
-const Matcher throwsIllegalJSRegExpException =
-    const Throws(isIllegalJSRegExpException);
-
-class _IllegalJSRegExpException extends TypeMatcher {
-  const _IllegalJSRegExpException() : super("IllegalJSRegExpException");
-  bool matches(item, MatchState matchState) => item is IllegalJSRegExpException;
-}
-
 /** A matcher for RangeErrors. */
 const isRangeError = const _RangeError();
 
 /** A matcher for functions that throw RangeError. */
 const Matcher throwsRangeError =
     const Throws(isRangeError);
 
 class _RangeError extends TypeMatcher {
   const _RangeError() : super("RangeError");
   bool matches(item, MatchState matchState) => item is RangeError;
@@ skipping 227 matching lines @@
       description.add(_featureDescription).add(' ').addDescriptionOf(_matcher);
 
   Description describeMismatch(item, Description mismatchDescription,
                                MatchState matchState, bool verbose) {
     mismatchDescription.add(_featureName).add(' ');
     _matcher.describeMismatch(matchState.state['feature'], mismatchDescription,
         matchState.state['innerState'], verbose);
     return mismatchDescription;
   }
 }