tests/test-mq-qsave.t

histedit: use hg.updaterepo() to avoid ui.{push|pop}buffer() hack

In some parts of code, we call hg.update() and surround that with
ui.pushbuffer() and ui.popbuffer() to suppress the output returned by
hg.update().

We have hg.updaterepo() which does not writes to UI and can be used instead.

Differential Revision: https://phab.mercurial-scm.org/D3862

  $ echo "[extensions]" >> $HGRCPATH
  $ echo "mq=" >> $HGRCPATH

  $ hg init

  $ echo 'base' > base
  $ hg ci -Ambase
  adding base

  $ hg qnew -mmqbase mqbase

  $ hg qsave
  $ hg qrestore 2
  restoring status: hg patches saved state