testing/{merlin,ocaml-{fileutils,gettext,ptmap,qcheck,qtest,sha}}: upgrade

Here are 3 OCaml aports I couldn't get to build in !34220 (closed), and another 4 that are upgraded, plus their dependencies.

This MR has a much cleaner commit log than !34220 (closed) and covers fewer aports.

I tried to keep my changes to the minimum required to get the aports to build. So, this should be quite merge-ready.