Fix a bug in bench that was running the driver on dune generated folders

Signed-off-by: Nathan Rebours <[email protected]>

bench/bench.ml

@@ -48,9 +48,10 @@ let time_run_blocking program args =
   timestamp_after -. timestamp_before
 
 (* Takes the path of a directory and returns a list of the full paths of the
-   files contained within it *)
+   files contained within it. Filters dot files and folders. *)
 let readdir_full_paths dir =
   Sys.readdir dir |> Array.to_list |> List.sort String.compare
+  |> List.filter (fun path -> path.[0] <> '.')
   |> List.map (Filename.concat dir)
 
 module Input = struct