Disable failing brows:news:cnn on webview system_health.common

Bug: 854683
Change-Id: I6cd308c8eadf151051916262c1d17530e85be0c1
TBR: charliea@chromium.org
NOTRY: true
Reviewed-on: https://chromium-review.googlesource.com/1108396Reviewed-by: Annie Sullivan <sullivan@chromium.org>
Commit-Queue: Annie Sullivan <sullivan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#568918}

tools/perf/expectations.config

@@ -339,6 +339,7 @@ crbug.com/736147 [ Android_One ] system_health.common_mobile/browse:social:tumbl
 crbug.com/803461 [ Nexus_5 ] system_health.common_mobile/browse:chrome:newtab [ Skip ]
 crbug.com/842163 [ Android_One ] system_health.common_mobile/browse:social:facebook_infinite_scroll [ Skip ]
 crbug.com/842163 [ Android_One ] system_health.common_mobile/browse:social:pinterest_infinite_scroll [ Skip ]
+crbug.com/854683 [ Android_Webview ] system_health.common_mobile/browse:news:cnn [ Skip ]
 crbug.com/852840 [ Android_Webview ] system_health.common_mobile/browse:media:youtube [ Skip ]
 
 # Benchmark: system_health.memory_desktop