dirstate: drop the now unused magic constants for the dirstate module
We no longer need them for the dirstate logic. We only need them in the
dirstate map (and parsers) logic.
This smell like progress.
Differential Revision: https://phab.mercurial-scm.org/D10964
edition = "2018"
max_width = 79
wrap_comments = true
error_on_line_overflow = true