Mark pkg/watcher/test/no_subscription_test as flaky on windows.

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
 
+[ $runtime == vm ]
+watcher/test/no_subscription_test: Pass, Fail # Issue 12107
+
 [ $compiler == none && $runtime == drt && $mode == debug]
 mdv/test/custom_element_bindings_test: Fail # Issue 11657
 
 [ $compiler == dart2js && $runtime == ff ]
 unittest/test/unittest_test: Pass, Timeout # http://dartbug.com/11473
 
 [ $runtime == d8 || $runtime == jsshell ]
 unittest/test/unittest_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 140 matching lines @@
 [ $runtime == dartium || $runtime == drt ]
 serialization/test/no_library_test: Skip # Expected Failure
 
 # Skip mdv tests on command line VM, they only run in the browser.
 [ $runtime == vm ]
 mdv: Skip
 
 [ $runtime == safari || $runtime == chrome || $runtime == ie9 || $runtime == ff || $runtime == dartium || $runtime == drt ]
 docgen/test/single_library_test: Skip # Uses dart:io