Remove duplicate lines from core.gyp*

We've got some dupes after r162052, so just pipe them through uniq.

TBR=schenney,ckocagil

Review URL: https://codereview.chromium.org/104483002

git-svn-id: svn://svn.chromium.org/blink/trunk@163202 bbb929c8-8fbe-4397-9dbb-9b2b20218538