Remove dead OpenType code

Also remove a bit of the exclude pattern for OpenType in core.gyp,
since it never matched anything: the exclusion is instead taken
care of by the directory exclude line.

R=abarth

Review URL: https://chromiumcodereview.appspot.com/23011052

git-svn-id: svn://svn.chromium.org/blink/trunk@156729 bbb929c8-8fbe-4397-9dbb-9b2b20218538