Disable page_cycler.typical_25 on windows, and session_restore.cold.typical_25 on linux.

tools/perf/benchmarks/page_cycler.py

Index: tools/perf/benchmarks/page_cycler.py
diff --git a/tools/perf/benchmarks/page_cycler.py b/tools/perf/benchmarks/page_cycler.py
index b9a0b8c971b3db86d998a9af4b179210338cda4b..54093d7c9a29038ff451eef0969aaed88bb154fc 100644
--- a/tools/perf/benchmarks/page_cycler.py
+++ b/tools/perf/benchmarks/page_cycler.py
@@ -1,6 +1,8 @@
 # Copyright (c) 2013 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 telemetry import test
 
 from measurements import page_cycler
@@ -103,6 +105,8 @@ class PageCyclerToughLayoutCases(test.Test):
 
 
 class PageCyclerTypical25(test.Test):
+  # crbug.com/273986: This test is really flakey on xp.
+  enabled = not sys.platform.startswith('win')
   test = page_cycler.PageCycler
   page_set = 'page_sets/typical_25.json'
   options = {'pageset_repeat_iters': 10}