tests/test-merge8.t

cborutil: port to Python 3

The only problem lurking in here was sorts of mismatched types. The
sorts are only for output stability in our tests (sigh), so we just
build a phony sort key using the __name__ of types so that we only
compare like types against each other. By pure luck, my awful sort key
matches the behavior we get "for free" in Python 2, so no test output
changes.

Differential Revision: https://phab.mercurial-scm.org/D3504

Test for changeset ba7c74081861
(update dirstate correctly for non-branchmerge updates)
  $ hg init a
  $ cd a
  $ echo a > a
  $ hg add a
  $ hg commit -m a
  $ cd ..
  $ hg clone a b
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd a
  $ hg mv a b
  $ hg commit -m move
  $ echo b >> b
  $ hg commit -m b
  $ cd ../b
  $ hg pull ../a
  pulling from ../a
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 2 changes to 1 files
  new changesets e3c9b40284e1:772b37f1ca37
  (run 'hg update' to get a working copy)
  $ hg update
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved

  $ cd ..