Redo "Fix for queue closed crash"

tests/compiler/dart2js_extra/mirror_enqueuer_regression_test.dart

+// Copyright (c) 2014, 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.
+
+// Regression test for 'staged' reflection.  MirrorsUsed pulls in static
+// functions, that pulls in more reflection.  This used to trigger a bug in
+// Enqueuer where the second set of pulled in definitions were unresolved.
+
+@MirrorsUsed(targets: const ["foo"])
+import 'dart:mirrors';
+
+final foo = reflect(reflect(9)).getField(#getField);
+
+void main() {}