Disable a failing perf test

Disabling perf test v8.browsing_mobile/browse:media:imgur:2019 on
Android Nexus6 WebView Perf.

TBR=crouleau@chromium.org
NOTRY=True

Bug: 1037905
Change-Id: I69f2cab841c944e00e4aa11c336f7422b877c417
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1982592Reviewed-by: John Chen <johnchen@chromium.org>
Commit-Queue: John Chen <johnchen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#727471}

tools/perf/expectations.config

@@ -480,6 +480,7 @@ crbug.com/1029465 [ android-nexus-6 android-webview ] v8.browsing_mobile/browse:
 crbug.com/1036141 [ android-webview ] v8.browsing_mobile/browse:shopping:lazada:2019 [ Skip ]
 crbug.com/1036143 [ android-pixel-2 ] v8.browsing_mobile/browse:chrome:omnibox:2019 [ Skip ]
 crbug.com/1037687 [ android ] v8.browsing_mobile/browse:social:pinterest_infinite_scroll:2019 [ Skip ]
+crbug.com/1037905 [ android-nexus-6 android-webview ] v8.browsing_mobile/browse:media:imgur:2019 [ Skip ]
 
 # Benchmark: v8.browsing_mobile-future
 # Disabled v8.browsing_mobile-future for capacity reasons while we update