Gardening: Mark timer-throttling-hidden-page.html as failing on WinXP

TBR=arv@chromium.org
NOTRY=true
BUG=412273

Review URL: https://codereview.chromium.org/539383005

git-svn-id: svn://svn.chromium.org/blink/trunk@181618 bbb929c8-8fbe-4397-9dbb-9b2b20218538