Remove all-passing expectation for testharness.js-based test

This useless -expected.txt file must have slipped in between r176164
(which removed all such expected files) and the follow-up PRESUBMIT
to prevent them from being added.

TBR=mlamouri@chromium.org
BUG=None

Review URL: https://codereview.chromium.org/382433003

git-svn-id: svn://svn.chromium.org/blink/trunk@178012 bbb929c8-8fbe-4397-9dbb-9b2b20218538