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

tools/perf/benchmarks/page_cycler.py

 # 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
 
 
 class PageCyclerBloat(test.Test):
   test = page_cycler.PageCycler
   page_set = 'page_sets/page_cycler/bloat.json'
   options = {'pageset_repeat_iters': 10}
 
@@ skipping 82 matching lines @@
   options = {'pageset_repeat_iters': 10}
 
 
 class PageCyclerToughLayoutCases(test.Test):
   test = page_cycler.PageCycler
   page_set = 'page_sets/tough_layout_cases.json'
   options = {'pageset_repeat_iters': 10}
 
 
 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}