tests/test-mq-qsave.t

run-tests: allow Test.run() to run multiple times

Test.run() can now be executed multiple times on the same Test instance.
This feature is currently unused and there are no plans to implement it.
The main reason for this work was to refactor testtmp, replacements, and
env to be run-time specific as opposed to Test instance specific.

  $ 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