upgrade: support the --quiet flag
The command is currently very verbose with a various bit of output being time
sensitive or randomized. The make invocation bulky and hard to match in the
test. We move various message from `ui.write` to `ui.status` in order for the
`--quiet` flag to have effect and helps the situation.
As a side benefit, we can replace the various redirection to > /dev/null with the --quiet flag.
Differential Revision: https://phab.mercurial-scm.org/D8429
$ 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