tests/test-dirstate-nonnormalset.t

changegroup: extract method that sorts nodes to send

The current implementation of narrowhg needs to influence the order in
which nodes are sent to the client. adgar@ and I think this is
fixable, but it's going to require pretty substantial time investment,
so in the interim we'd like to extract this method.

I think it makes the group() code a little more obvious, as it took us
a couple of tries to isolate the exact behavior we were observing.

  $ cat >> $HGRCPATH << EOF
  > [ui]
  > logtemplate="{rev}:{node|short} ({phase}) [{tags} {bookmarks}] {desc|firstline}\n"
  > [extensions]
  > dirstateparanoidcheck = $TESTDIR/../contrib/dirstatenonnormalcheck.py
  > [experimental]
  > nonnormalparanoidcheck = True
  > [devel]
  > all-warnings=True
  > EOF
  $ mkcommit() {
  >    echo "$1" > "$1"
  >    hg add "$1"
  >    hg ci -m "add $1"
  > }

  $ hg init testrepo
  $ cd testrepo
  $ mkcommit a
  $ mkcommit b
  $ mkcommit c
  $ hg status