remove tests for undrifted particles in send/recv as not all sent/recvd...

remove tests for undrifted particles in send/recv as not all sent/recvd particles are drifted, only those that are needed. note that undrifted particles will still be caught in the interaction functions.

src/runner.c

@@ -1544,11 +1544,6 @@ void runner_do_recv_part(struct runner *r, struct cell *c, int clear_sorts,
       time_bin_min = min(time_bin_min, parts[k].time_bin);
       time_bin_max = max(time_bin_max, parts[k].time_bin);
       h_max = max(h_max, parts[k].h);
-
-#ifdef SWIFT_DEBUG_CHECKS
-      if (parts[k].ti_drift != ti_current)
-        error("Received un-drifted particle !");
-#endif
     }
 
     /* Convert into a time */

src/scheduler.c

@@ -1363,11 +1363,6 @@ void scheduler_enqueue(struct scheduler *s, struct task *t) {
         } else if (t->subtype == task_subtype_xv ||
                    t->subtype == task_subtype_rho ||
                    t->subtype == task_subtype_gradient) {
-#ifdef SWIFT_DEBUG_CHECKS
-          for (int k = 0; k < t->ci->count; k++)
-            if (t->ci->parts[k].ti_drift != s->space->e->ti_current)
-              error("Sending un-drifted particle !");
-#endif
           err = MPI_Isend(t->ci->parts, t->ci->count, part_mpi_type,
                           t->cj->nodeID, t->flags, MPI_COMM_WORLD, &t->req);
           // message( "sending %i parts with tag=%i from %i to %i." ,