rust-dirstate-status: add call to rust-fast path for `dirstate.status` The reasoning behind this patch is explained in the first patch of the series. Differential Revision: https://phab.mercurial-scm.org/D7060

rust-dirstate-status: rust-cpython bindings for `dirstate.status` The ref-sharing mechanism has improved, but its ergonomics still left a bit to be desired, as expected. Differential Revision: https://phab.mercurial-scm.org/D7059