Added a "Skip" expectation to allow test runs to avoid known timeouts

tools/telemetry/telemetry/page/page_runner.py

Index: tools/telemetry/telemetry/page/page_runner.py
diff --git a/tools/telemetry/telemetry/page/page_runner.py b/tools/telemetry/telemetry/page/page_runner.py
index dff83ef5e056d51fc73cbd02297ebd346921d5a2..de0ebffc82bc9513000be2fd80347580a3260e2b 100644
--- a/tools/telemetry/telemetry/page/page_runner.py
+++ b/tools/telemetry/telemetry/page/page_runner.py
@@ -367,6 +367,10 @@ def _CheckArchives(page_set, pages, results):
 
 
 def _RunPage(test, page, state, expectation, results, finder_options):
+  if expectation == 'skip':
+    logging.warning('Skipped %s' % page.url)
+    return
+
   logging.info('Running %s' % page.url)
 
   page_state = PageState()