Remove a broken test from loop_handler_SUITE
Remove a broken test from loop_handler_SUITE

The feature was removed in Cowboy 2.0. An alternative to obtain
the same behavior will be introduced as cowboy_req:read_body_async/1.

turtleDeng/cowboy,CrankWheel/cowboy,K2InformaticsGmbH/cowboy,hairyhum/cowboy,kivra/cowboy,ninenines/cowboy