Avoid infinite loop if const constructor redirects don't reach a fixed point.

tests/language/regress_23038_test.dart

Index: tests/language/regress_23038_test.dart
diff --git a/tests/compiler/dart2js/dart2js_batch2_run.dart b/tests/language/regress_23038_test.dart
similarity index 64%
copy from tests/compiler/dart2js/dart2js_batch2_run.dart
copy to tests/language/regress_23038_test.dart
index aee55ef18e5fa77c47bcbf53f5c16125299ed77a..643ca7853d16ffd88d18613f6084de42772e8667 100644
--- a/tests/compiler/dart2js/dart2js_batch2_run.dart
+++ b/tests/language/regress_23038_test.dart
@@ -2,9 +2,14 @@
 // 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.
 
-@notExisting
-var x;
+class C<T> {
+  const
+    factory /// 01: compile-time error
+    C()
+    = C<C<T>> /// 01: continued
+    ;
+}
 
 main() {
-  print(x);
+  const C<int>();
 }