[tools/perf] Disable flaky browse:social:facebook_infinite_scroll:2018

Flaky crashes in prediction_metrics_handler.cc

NOTRY=true
TBR=crouleau@chromium.org

Bug: 1017661
Change-Id: I5a17d19a19231bbc2d5b36a7d20d12bd5c639ec5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1879232Reviewed-by: Juan Antonio Navarro Pérez <perezju@chromium.org>
Commit-Queue: Juan Antonio Navarro Pérez <perezju@chromium.org>
Cr-Commit-Position: refs/heads/master@{#709409}

tools/perf/expectations.config

@@ -389,6 +389,7 @@ crbug.com/961417 [ android-go ] system_health.memory_mobile/browse:social:tumblr
 crbug.com/1002640 [ android-pixel-2 ] system_health.memory_mobile/browse:chrome:newtab [ Skip ]
 crbug.com/1002665 [ android-pixel-2 ] system_health.memory_mobile/browse:chrome:omnibox [ Skip ]
 crbug.com/1017661 [ android-nexus-5x ] system_health.memory_mobile/browse:media:flickr_infinite_scroll [ Skip ]
+crbug.com/1017661 [ android-nexus-5x ] system_health.memory_mobile/browse:social:facebook_infinite_scroll:2018 [ Skip ]
 
 # Benchmark: tab_switching.typical_25
 crbug.com/747026 [ mac ] tab_switching.typical_25/multitab:misc:typical24 [ Skip ]