Increase the allowed heap size for slow consumer test. We hit the limit in dartium x64 checked mode.

tests/lib/lib.status

Index: tests/lib/lib.status
diff --git a/tests/lib/lib.status b/tests/lib/lib.status
index e99b4313b75f1a224a53edac9a3638075c8d64be..ce543edbfb06daafe75747cf3c4039e5d4423b4f 100644
--- a/tests/lib/lib.status
+++ b/tests/lib/lib.status
@@ -2,10 +2,6 @@
 # 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.
 
-[ ($runtime == drt || $runtime == dartium) && $checked ]
-# Issue 9345. We are getting out of memory situations on the dartium buildbot in checked mode.
-async/slow_consumer3_test: Pass, Fail
-
 # The scalarlist library is not supported by dart2js or dart2dart yet.
 [ $compiler == dart2js  || $compiler == dart2dart ]
 scalarlist/*: Skip