Disable load:tools:dropbox:2019 for all android bots.

NOTRY=true
TBR=crouleau@chromium.org
CC=pasko@chromium.org,crouleau@chromium.org,chrome-android-perf-status@chromium.org,charliea@chromium.org,sullivan@chromium.org,tdresser@chromium.org,chrome-speed-metrics-dev@chromium.org
BUG=1039277

Change-Id: Idb28cec9e5a6bdaecfd9644e66089b4fd83e6ceb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1980184Reviewed-by: Stephen Nusko <nuskos@chromium.org>
Commit-Queue: Stephen Nusko <nuskos@chromium.org>
Auto-Submit: Stephen Nusko <nuskos@chromium.org>
Cr-Commit-Position: refs/heads/master@{#728536}

tools/perf/expectations.config

@@ -424,6 +424,7 @@ crbug.com/1017661 [ android-nexus-5x ] system_health.memory_mobile/browse:social
 crbug.com/1017661 [ android-nexus-5x ] system_health.memory_mobile/browse:tech:discourse_infinite_scroll:2018 [ Skip ]
 crbug.com/1036143 [ android-pixel-2 ] system_health.memory_mobile/browse:chrome:omnibox:2019 [ Skip ]
 crbug.com/1037687 [ android ] system_health.memory_mobile/browse:social:pinterest_infinite_scroll:2019 [ Skip ]
+crbug.com/1039277 [ android ] system_health.memory_mobile/load:tools:dropbox:2019 [ Skip ]
 
 # Benchmark: tab_switching.typical_25
 crbug.com/747026 [ mac ] tab_switching.typical_25/multitab:misc:typical24 [ Skip ]