Add Layout test to check <select> with -webkit-autofil style

R=tkent@chromium.org
BUG=58719

Review URL: https://codereview.chromium.org/214693004

git-svn-id: svn://svn.chromium.org/blink/trunk@170225 bbb929c8-8fbe-4397-9dbb-9b2b20218538