Disable flaky SystemHealthBenchmarkSmokeTest.

TBR=nednguyen@chromium.org,perezju@chromium.org

Bug: 837397
Change-Id: If29d26fefee43107ba6d51c3818e6fed37eaea7c
Reviewed-on: https://chromium-review.googlesource.com/1032876
Commit-Queue: John Budorick <jbudorick@chromium.org>
Reviewed-by: John Budorick <jbudorick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#554543}

tools/perf/expectations.config

@@ -287,6 +287,7 @@ crbug.com/799106 [ Win ] system_health.memory_desktop/browse:media:flickr_infini
 crbug.com/812807 [ Linux ] system_health.memory_desktop/browse:media:tumblr [ Skip ]
 crbug.com/836406 [ Linux ] system_health.memory_desktop/browse:news:flipboard [ Skip ]
 crbug.com/836407 [ Linux ] system_health.memory_desktop/browse:tools:maps [ Skip ]
+crbug.com/837397 [ Linux ] system_health.memory_desktop/load_accessibility:shopping:amazon [ Skip ]
 crbug.com/836447 [ ChromeOS ] system_health.memory_desktop/multitab:misc:typical24 [ Skip ]
 
 # Benchmark: system_health.memory_mobile