Gardening: Flaky timeout of use-same-database-in-page-and-workers.html.

BUG=310866
TBR=jsbell@chromium.org

Review URL: https://codereview.chromium.org/37993003

git-svn-id: svn://svn.chromium.org/blink/trunk@160396 bbb929c8-8fbe-4397-9dbb-9b2b20218538