Remove dead code hiding behind ENABLE(TOUCH_EVENT_TRACKING).
<https://webkit.org/b/122719>

Reviewed by Antti Koivisto.

Nobody is building with this flag, and it has broken-looking code
behind it anyway. Nuke from orbit.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@157361 268f45cc-cd09-0410-ab3c-d52691b4dbfc