Unreviewed, rolling out r175690.
https://bugs.webkit.org/show_bug.cgi?id=138460

We are not ready to run layout tests using the network process
yet (Requested by KaL on #webkit).

Reverted changeset:

"[GTK] Run layout tests using the network process"
https://bugs.webkit.org/show_bug.cgi?id=138428
http://trac.webkit.org/changeset/175690

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@175693 268f45cc-cd09-0410-ab3c-d52691b4dbfc