tests/test-merge8.t

branch: operate on branch names in local string space where possible

Previously, branch names were ideally manipulated as UTF-8 strings,
because they were stored as UTF-8 in the dirstate and the changelog
and could not be safely converted to the local encoding and back.

However, only about 80% of branch name code was actually using the
right encoding conventions. This patch uses the localstr addition to
allow working on branch names as local strings, which simplifies
handling so that the previously incorrect code becomes correct.

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
  (run 'hg update' to get a working copy)
  $ hg update
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved