tests/test-hgk.t

win32: assign winstdout to sys.__stdout__ as well (issue2888)

On Windows sys.stdout was being replaced with winstdout, which caused
util.system() to redirect its output (due to 406b6d7bdcb9). That causes
interactive tools (such as vim) to stop working.

Minimal hgk check

  $ echo "[extensions]" >> $HGRCPATH
  $ echo "hgk=" >> $HGRCPATH
  $ hg init repo
  $ cd repo
  $ echo a > a
  $ hg ci -Am adda
  adding a
  $ hg debug-cat-file commit 0
  tree a0c8bcbbb45c
  parent 000000000000
  author test 0 0
  committer test 0 0
  revision 0
  branch default
  
  adda