------ Test dirstate._dirs refcounting

  $ hg init t

  $ cd t

  $ mkdir -p a/b/c/d

  $ touch a/b/c/d/x

  $ touch a/b/c/d/y

  $ touch a/b/c/d/z

  $ hg ci -Am m

  adding a/b/c/d/x

  adding a/b/c/d/y

  adding a/b/c/d/z

  $ hg mv a z

  moving a/b/c/d/x to z/b/c/d/x

  moving a/b/c/d/y to z/b/c/d/y

  moving a/b/c/d/z to z/b/c/d/z

  $ cd ..

Issue1790: dirstate entry locked into unset if file mtime is set into

the future

Prepare test repo:

  $ hg init u

  $ cd u

  $ echo a > a

  $ hg add

  adding a

  $ hg ci -m1

Set mtime of a into the future:

  $ touch -t 202101011200 a

Status must not set a's entry to unset (issue1790):

  $ hg status

  $ hg debugstate

  n 644          2 2021-01-01 12:00:00 a

  $ cd ..