qmp-test is for QMP protocol tests.  Commit e4a426e7 added generic,
basic tests of query commands to it.  Move them to their own test
program qmp-cmd-test, to keep qmp-test focused on the protocol.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180823164025.12553-6-armbru@redhat.com>