experimental: drop bisect_ppx from testing dependencies

Author: psafont

packages/bisect_ppx/bisect_ppx.2.8.3/opam

@@ -12,7 +12,6 @@ depends: [
   "alcotest" {with-test}
   "astring"
   "base-unix"
-  "bisect_ppx" {with-test}
   "clock" {= version & with-test}
   "fd-send-recv" {>= "2.0.0"}
   "fmt"