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

See bug for context.

Bug: chromium:1139057
Change-Id: I634955a854d11c5dbe1970b23487b4f5c045a955
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2477237Reviewed-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@{#817755}

tools/perf/expectations.config

@@ -377,6 +377,7 @@ crbug.com/1112337 [ android ] system_health.memory_mobile/browse:news:cricbuzz:2
 crbug.com/1113921 [ android-go ] system_health.memory_mobile/load:tools:dropbox:2019 [ Skip ]
 crbug.com/1128019 [ android-pixel-2 ] system_health.memory_mobile/load:tools:dropbox:2019 [ Skip ]
 crbug.com/1128019 [ android-nexus-5x ] system_health.memory_mobile/load:tools:dropbox:2019 [ Skip ]
+crbug.com/1139057 [ mobile ] system_health.memory_mobile/browse:social:facebook:2019 [ Skip ]
 
 # Benchmark: tab_switching.typical_25
 crbug.com/747026 [ mac ] tab_switching.typical_25/multitab:misc:typical24 [ Skip ]