dirstate-tree: Add a dirstate-v1-tree variant of some tests The `dirstate-v1` variant has the previous behavior. `dirstate-v1-tree` uses the same format on disk, but uses the new `DirstateMap` with a tree data structure and the new `status` algorithm. These were untested so far. Differential Revision: https://phab.mercurial-scm.org/D10698