feat(oxcaml): parameterised inline_tests

[art-w]

Follow-up on the instantiation of parameterised libraries #12561 to support inline_tests (marking this PR as a draft since only the last commit is new).

To run the inline tests of a parameterised library, the user should specify with (arguments ...) which implementation of the parameters to use, as otherwise the test can't be ran.

Fix #12110

[Alizter]

Is ppx_expect building in oxcaml now?

[art-w]

ppx_inline_test works yes, but I think the nix flake is using a more edgy version of OxCaml than the one published in their opam-repo... I'm looking into it.