Enable hide_layers2.html (closes #8769)

This was apparently fixed by #10082.
servo · bors-servo · Aug 10, 2016 · Aug 10, 2016 · Aug 10, 2016 · 7f8cce6beb246e8db4d4cabff6820db475f7d20c
commit 7f8cce6beb246e8db4d4cabff6820db475f7d20c
diff --git a/etc/ci/former_intermittents_wpt.txt b/etc/ci/former_intermittents_wpt.txt
@@ -0,0 +1 @@
+/_mozilla/mozilla/css/iframe/hide_layers2.html
diff --git a/tests/wpt/mozilla/meta/css/iframe/hide_layers2.html.ini b/tests/wpt/mozilla/meta/css/iframe/hide_layers2.html.ini