Removing GardinerMod font after it got merged in Chromium's third_party

The GardinerMod font is side loaded by content shell
and used for layout testing and for this reason got added
to the Chromium repo in r281738. We do not
need the redundant copy in Blink anymore.

BUG=381684

Review URL: https://codereview.chromium.org/394453002

git-svn-id: svn://svn.chromium.org/blink/trunk@178088 bbb929c8-8fbe-4397-9dbb-9b2b20218538