Remove battery-status/page-visibility.html test expectation.

Test back to normal following r183158.

TBR=jsbell@chromium.org
BUG=419515
NOTRY=true

Review URL: https://codereview.chromium.org/610563003

git-svn-id: svn://svn.chromium.org/blink/trunk@183161 bbb929c8-8fbe-4397-9dbb-9b2b20218538