migration-test: cpr-transfer

migration-test: cpr-transfer

Add a migration test for cpr-transfer mode.  Defer the connection to the
target monitor, else the test hangs because in cpr-transfer mode QEMU does
not listen for monitor connections until we send the migrate command to
source QEMU.

To test -incoming defer, send a migrate incoming command to the target,
after sending the migrate command to the source, as required by
cpr-transfer mode.

Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Link: https://lore.kernel.org/r/1736967650-129648-24-git-send-email-steven.sistare@oracle.com
[only allocate in_channels when needed]
Signed-off-by: Fabiano Rosas <farosas@suse.de>