Remove executable bit from a file which isn't executable

Done using svn propdel svn:executable and commited manually.

Fixing a single file first to verify that it will work.

BUG=none

Review URL: https://codereview.chromium.org/68773002/



git-svn-id: svn://svn.chromium.org/blink/trunk@161906 bbb929c8-8fbe-4397-9dbb-9b2b20218538