Reenable facebook and pinterest infinite scroll on Android One

A recent bisect in the linked bug suggests that they aren't flaky
anymore.

NOTRY=true
TBR=nednguyen@chromium.org

Bug: 842163
Change-Id: I79442bf895ff3596f1b1c8ae3db8ccb596041e78
Reviewed-on: https://chromium-review.googlesource.com/1146765Reviewed-by: Charlie Andrews <charliea@chromium.org>
Commit-Queue: Charlie Andrews <charliea@chromium.org>
Cr-Commit-Position: refs/heads/master@{#577170}

tools/perf/expectations.config

@@ -263,8 +263,6 @@ crbug.com/798536 [ Android ] system_health.common_mobile/background:news:nytimes
 crbug.com/798536 [ Android ] system_health.common_mobile/load:games:spychase [ Skip ]
 crbug.com/736147 [ Android_One ] system_health.common_mobile/browse:social:tumblr_infinite_scroll [ Skip ]
 crbug.com/803461 [ Nexus_5 ] system_health.common_mobile/browse:chrome:newtab [ Skip ]
-crbug.com/842163 [ Android_One ] system_health.common_mobile/browse:social:facebook_infinite_scroll [ Skip ]
-crbug.com/842163 [ Android_One ] system_health.common_mobile/browse:social:pinterest_infinite_scroll [ Skip ]
 
 # Benchmark: system_health.memory_desktop
 crbug.com/728576 [ Mac ] system_health.memory_desktop/browse:news:cnn [ Skip ]