Disable stories on system_health.common_mobile Android

TBR=nednguyen@google.com
NOTRY=true

Bug: 798536
Change-Id: Ie01236ca17cd385de37e3f97730258aed9832544
Reviewed-on: https://chromium-review.googlesource.com/849013Reviewed-by: Simon Hatch <simonhatch@chromium.org>
Commit-Queue: Simon Hatch <simonhatch@chromium.org>
Cr-Commit-Position: refs/heads/master@{#526727}

tools/perf/expectations.config

@@ -192,6 +192,8 @@ crbug.com/708300 [ Android ] system_health.common_mobile/browse:shopping:flipkar
 crbug.com/738854 [ Nexus_5X ] system_health.common_mobile/load:tools:drive [ Skip ]
 crbug.com/738854 [ Android_Webview ] system_health.common_mobile/load:tools:drive [ Skip ]
 crbug.com/797261 [ Android_Webview ] system_health.common_mobile/load:games:spychase [ Skip ]
+crbug.com/798536 [ Android ] system_health.common_mobile/background:news:nytimes [ Skip ]
+crbug.com/798536 [ Android ] system_health.common_mobile/load:games:spychase [ Skip ]
 
 # Benchmark: system_health.memory_desktop
 crbug.com/728576 [ Mac ] system_health.memory_desktop/browse:news:cnn [ Skip ]