[tools/perf] Disably stories flaky on internal bots

Disable some stories currently flaking on internal perf bots.

TBR=nednguyen@google.com
NOTRY=true

Bug: 892704
Change-Id: I9d9ddf82c0818598c5c0b655f1813ad341feea49
Reviewed-on: https://chromium-review.googlesource.com/c/1293578Reviewed-by: Juan Antonio Navarro Pérez <perezju@chromium.org>
Commit-Queue: Juan Antonio Navarro Pérez <perezju@chromium.org>
Cr-Commit-Position: refs/heads/master@{#601574}

tools/perf/expectations.config

@@ -269,8 +269,7 @@ crbug.com/842731 [ Android_One ] system_health.memory_mobile/background:news:nyt
 crbug.com/843547 [ Android_Go ] system_health.memory_mobile/background:news:nytimes [ Skip ]
 crbug.com/852888 [ Nexus_5X ] system_health.memory_mobile/background:news:nytimes [ Skip ]
 crbug.com/859500 [ Nexus_5X ] system_health.memory_mobile/browse:social:tumblr_infinite_scroll [ Skip ]
-crbug.com/871708 [ Android_Go Android_Webview ] system_health.memory_mobile/browse:social:facebook_infinite_scroll [ Skip ]
-crbug.com/871708 [ Android_One Android_Webview ] system_health.memory_mobile/browse:social:facebook_infinite_scroll [ Skip ]
+crbug.com/871708 [ Android_Webview ] system_health.memory_mobile/browse:social:facebook_infinite_scroll [ Skip ]
 crbug.com/865400 [ Pixel_2 ] system_health.memory_mobile/background:news:nytimes [ Skip ]
 crbug.com/877648 [ Android ] system_health.memory_mobile/long_running:tools:gmail-background [ Skip ]
 crbug.com/877648 [ Android ] system_health.memory_mobile/long_running:tools:gmail-foreground [ Skip ]
@@ -282,10 +281,12 @@ crbug.com/880652 [ Nexus_5X ] system_health.memory_mobile/browse:shopping:avito
 crbug.com/883652 [ Android_One ] system_health.memory_mobile/browse:social:tumblr_infinite_scroll [ Skip ]
 crbug.com/883652 [ Android_One ] system_health.memory_mobile/browse:news:cnn:2018 [ Skip ]
 crbug.com/883652 [ Android_One ] system_health.memory_mobile/browse:news:cnn [ Skip ]
+crbug.com/892704 [ Android_One ] system_health.memory_mobile/load:news:cnn [ Skip ]
 crbug.com/883652 [ Android_One ] system_health.memory_mobile/browse:news:toi [ Skip ]
 crbug.com/883652 [ Nexus_5 ] system_health.memory_mobile/browse:shopping:avito [ Skip ]
 crbug.com/893873 [ Nexus_5X ] system_health.memory_mobile/load:news:washingtonpost [ Skip ]
 crbug.com/896851 [ Android ] system_health.memory_mobile/background:tools:gmail [ Skip ]
+crbug.com/892704 [ Android_Webview ] system_health.memory_mobile/browse:tech:discourse_infinite_scroll:2018 [ Skip ]
 
 # Benchmark: tab_switching.typical_25
 crbug.com/747026 [ Mac ] tab_switching.typical_25/multitab:misc:typical24 [ Skip ]