… prereqs

…e_step_3

you can find them in the ocaml/ directory, outside of the
generated subdirectories.

you can now find them in the ocaml/ directory,
outside of the generated/ subdirectories

…ut ocamlbuild

It only contains binaries and generated files

…e_step_2

…ne_step_2

Tests files (src/tests) make heavy use of top-level effects to
initialize a typechecker environment and load some definitions, among
other things.

If they are linked with everything else into fstar-lib, then
 1- the compiler will include them, which is a bit of bloat
 2- the compiler will be side effected by them causing some error
    message tests to fail as Tahina noticed.
 3- applications (which currently use this library) will also
    contain the tests and initialize them on program load, which
    is terrible.

This patch then moves all of the generation of FStar_Test_* modules
into ocaml/fstar-test instead of ocaml/fstar-lib. Dune takes care of the
rest. It would be nice for this way of splitting modules to be
standardized and somehow more easily configurable.

The actual patch is twofold: a SED edit of the .depend file, and a
change to the extraction rule to decide which directory a file goes to.
It does not really make sense to have to edit both... but there are
several limitations to our current Makefiles (see also #1978).

With @tahina-pro. This is suboptimal since it installs a fstar_tests.exe
program in the user's /bin directory, which serves no purpose. However
avoiding this and still being able to run tests in CI (or locally) takes
some refactoring however, so we are postponing it.

…stall

…ne_step_2

this is currently also building the ulibfs nuget package
and including it into the binary package

…ne_step_2