Disable system_health.common_mobile/browse:social:facebook:2019

This test sometimes hangs. Example - https://chrome-isolated.appspot.com/browse?namespace=default-gzip&digest=48d751774f963fcbdfae61d09bcd342ec023dc30&as=benchmark_log.txt

Bug: chromium:1139057
Change-Id: Ib019d9d8d721fcb4de22d2b1f8746d3edefb9d12
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2500484Reviewed-by: John Chen <johnchen@chromium.org>
Commit-Queue: Ryan Heise <heiserya@google.com>
Auto-Submit: Ryan Heise <heiserya@google.com>
Cr-Commit-Position: refs/heads/master@{#821362}

tools/perf/expectations.config

@@ -315,6 +315,7 @@ crbug.com/1112337 [ android ] system_health.common_mobile/browse:news:cricbuzz:2
 crbug.com/1113921 [ android-go ] system_health.common_mobile/load:tools:dropbox:2019 [ Skip ]
 crbug.com/1128019 [ android-pixel-2 ] system_health.common_mobile/load:tools:dropbox:2019 [ Skip ]
 crbug.com/1128019 [ android-nexus-5x ] system_health.common_mobile/load:tools:dropbox:2019 [ Skip ]
+crbug.com/1139057 [ mobile ] system_health.common_mobile/browse:social:facebook:2019 [ Skip ]
 
 # Benchmark: system_health.memory_desktop
 crbug.com/984599 [ linux ] system_health.memory_desktop/long_running:tools:gmail-foreground [ Skip ]