dont send was_killed to forkserver more than once (#175)

Co-authored-by: galtashma <gal.tashma@swg.local>

libafl/src/executors/forkserver.rs

@@ -353,6 +353,9 @@ where
             .executor
             .forkserver_mut()
             .write_ctl(last_run_timed_out)?;
+
+        self.executor.forkserver_mut().set_last_run_timed_out(0);
+
         if send_len != 4 {
             return Err(Error::Forkserver(
                 "Unable to request new process from fork server (OOM?)".to_string(),