Revert "Re-enable load:media:soundcloud for webview on system_health.common_mobile."

This reverts commit cfdb3952.

Reason for revert: Story is still failing

Original change's description:
> Re-enable load:media:soundcloud for webview on system_health.common_mobile.
> 
> It's passing in perf tryjobs.
> 
> Bug: 787001
> Change-Id: Ie9a74b141d6dd610a1bfab3d9d9ea79b40dafc48
> TBR: tdresser@chromium.org
> Reviewed-on: https://chromium-review.googlesource.com/1174632
> Reviewed-by: Annie Sullivan <sullivan@chromium.org>
> Commit-Queue: Annie Sullivan <sullivan@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#582944}

NOTRY=true
TBR=sullivan@chromium.org

Bug: 787001
Change-Id: If734162c4815ec7c1a988343859b80556cce6044
Reviewed-on: https://chromium-review.googlesource.com/1178001
Commit-Queue: Charlie Andrews <charliea@chromium.org>
Reviewed-by: Charlie Andrews <charliea@chromium.org>
Cr-Commit-Position: refs/heads/master@{#583705}

tools/perf/expectations.config

@@ -182,6 +182,7 @@ crbug.com/846022 [ Linux ] system_health.common_desktop/browse:social:twitter_in
 
 # Benchmark: system_health.common_mobile
 crbug.com/714650 [ Android ] system_health.common_mobile/browse:news:globo [ Skip ]
+crbug.com/787001 [ Android_Webview ] system_health.common_mobile/load:media:soundcloud [ Skip ]
 crbug.com/708300 [ Android ] system_health.common_mobile/browse:shopping:flipkart [ Skip ]
 crbug.com/738854 [ Nexus_5X ] system_health.common_mobile/load:tools:drive [ Skip ]
 crbug.com/738854 [ Android_Webview ] system_health.common_mobile/load:tools:drive [ Skip ]