scripts: add python_qmp_updater.py

scripts: add python_qmp_updater.py

A script, to update the pattern

    result = self.vm.qmp(...)
    self.assert_qmp(result, 'return', {})

(and some similar ones) into

    self.vm.cmd(...)

Used in the next commit
    "python: use vm.cmd() instead of vm.qmp() where appropriate"

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 20231006154125.1068348-15-vsementsov@yandex-team.ru
Signed-off-by: John Snow <jsnow@redhat.com>