CLEANUP: stream: remove an obsolete debugging test

The test consisted in checking that there was always a timeout on a
stream's task and was only enabled when built in development mode,
but 1) it is never tested and 2) if it had been tested it would have
been noticed that it triggers a bit too easily on the CLI. Let's get
rid of this old one.
diff --git a/src/stream.c b/src/stream.c
index 2b2d399..f0c7ad2 100644
--- a/src/stream.c
+++ b/src/stream.c
@@ -2634,11 +2634,6 @@
 			now_ms, t->expire, req->rex, req->wex, req->analyse_exp,
 			res->rex, res->wex, si_f->exp, si_b->exp, si_f->state, si_b->state);
 
-#ifdef DEBUG_DEV
-		/* this may only happen when no timeout is set or in case of an FSM bug */
-		if (!tick_isset(t->expire))
-			ABORT_NOW();
-#endif
 		s->pending_events &= ~(TASK_WOKEN_TIMER | TASK_WOKEN_RES);
 		stream_release_buffers(s);
 		/* We may have free'd some space in buffers, or have more to send/recv, try again */