Factor failing tests out of language/async_star_test.dart

tests/language/async_star_regression_fisk_test.dart

+// Copyright (c) 2015, 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.
+
+// This test may crash dart2js.
+
+import "dart:async";
+import "package:expect/expect.dart";
+import "package:async_helper/async_helper.dart";
+
+main() {
+  var res = [];
+  fisk() async* {
+    res.add("+fisk");
+    try {
+      for (int i = 0; i < 2; i++) {
+        yield await new Future.microtask(() => i);
+      }
+    } finally {
+      res.add("-fisk");
+    }
+  }
+
+  fugl(int count) async {
+    res.add("fisk $count");
+    try {
+      await for(int i in fisk().take(count)) res.add(i);
+    } finally {
+      res.add("done");
+    }
+  }
+
+  asyncStart();
+  fugl(3).whenComplete(() => fugl(2))
+      .whenComplete(() => fugl(1))
+      .whenComplete(() {
+    Expect.listEquals(res,
+        ["fisk 3", "+fisk", 0, 1, "-fisk", "done",
+         "fisk 2", "+fisk", 0, 1, "-fisk", "done",
+         "fisk 1", "+fisk", 0, "done", "-fisk", ]);
+    asyncEnd();
+  });
+}