Expand coverage of an entry for crypto/worker-subtle-crypto-concurrent.html.

BUG=409767
TBR=arv@chromium.org

Review URL: https://codereview.chromium.org/528113004

git-svn-id: svn://svn.chromium.org/blink/trunk@181278 bbb929c8-8fbe-4397-9dbb-9b2b20218538