Mark pkg/crypto/test/base64_test as timing out on IE in checked mode

pkg/pkg.status

 # 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.
 
 # Don't run any test-like files that show up in packages directories. It
 # shouldn't be necessary to run "pub install" in these packages, but if you do
 # it shouldn't break the tests.
 */packages/*/*: Skip
 */*/packages/*/*: Skip
 */*/*/packages/*/*: Skip
 
 # Skip non-test files ending with "_test".
 scheduled_test/lib/*: Skip
 
 scheduled_test/test/scheduled_server_test: Pass, Fail, Slow, Crash # Issue 9231, 9582
 scheduled_test/test/scheduled_process_test: Pass, Slow # Issue 9231
 
 # Skip test not runnable via test.dart
 third_party/html5lib/test/dom_compat_test: Skip
 
 [ $compiler == dart2js && $runtime == d8 ]
 unmodifiable_collection/test/unmodifiable_collection_test: Pass, Fail # Issue 12429
 
 [ $compiler == dart2js ]
 analyzer_experimental/test/generated/ast_test: Fail #Issue 12341
 
+[ $compiler == dart2js && $checked && $runtime == ie9 ]
+crypto/test/base64_test: Timeout # Issue 12486
+
 [ $compiler == dart2js && ($runtime == d8 || $runtime == drt) ]
 crypto/test/hmac_sha256_test: Pass, Fail # v8 bug: Issue 12293
 crypto/test/sha1_test: Pass, Fail # v8 bug: Issue 12293
 crypto/test/sha256_test: Pass, Fail # v8 bug: Issue 12293
 path/test/relative_test: Pass, Fail # v8 bug: Issue 12293
 
 [ $runtime == d8 || $runtime == jsshell ]
 unittest/test/unittest_nested_groups_setup_teardown_test: Pass, Fail # http://dartbug.com/10109
 stack_trace/test/vm_test: Fail, OK # VM-specific traces
 sequence_zip/test/stream_test: Fail, OK # Timers are not supported.
@@ skipping 159 matching lines @@
 
 # Skip tests on the VM if the package depends on dart:html
 [ $runtime == vm ]
 custom_element: Skip
 mdv: Skip
 mutation_observer: Skip
 third_party/html5lib/test/browser/browser_test: Skip
 
 [ $runtime == safari || $runtime == chrome || $runtime == ie9 || $runtime == ff || $runtime == dartium || $runtime == drt ]
 docgen/test/single_library_test: Skip # Uses dart:io