Nobody has answered the question, so here goes.
DXB-LAX 8339 nm 15.02 at M.84
DXB-IAH 8168 nm 14.43 at M.84
Figures for a B777, .84 cruise, nil wind, 207 min ETOPS and great circle tracks.
http://gc.kls2.com/ try this link and see for yourself.
The A340 being an obviously superior aircraft can fly direct.
