Added update_test_expectations script to remove non-flaky test expectations.

third_party/WebKit/Tools/Scripts/update-test-expectations

Index: third_party/WebKit/Tools/Scripts/update-test-expectations
diff --git a/third_party/WebKit/Tools/Scripts/update-test-expectations b/third_party/WebKit/Tools/Scripts/update-test-expectations
new file mode 100755
index 0000000000000000000000000000000000000000..007ff363cb4efe1e9d8a8354454af0b15250c8ba
--- /dev/null
+++ b/third_party/WebKit/Tools/Scripts/update-test-expectations
@@ -0,0 +1,12 @@
+#!/usr/bin/python
+#
+# Copyright 2016 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import sys
+
+from webkitpy.common import host
+from webkitpy.layout_tests import update_test_expectations
+
+update_test_expectations.main(host.Host(), sys.argv[1:])