CI: fix waiting for final test message

CI: fix waiting for final test message

Expect normally discards initial part of its buffer after matching the
patter, before looking for the next one. If both PASSED and LOG_MSG
happen to be in the buffer at the same time, depending on their order,
only one will be matched and the waiting for the other will timeout.
Example expect -d output of this happening (parts eclipsed for brevity):

    expect: does "\r\r\r\nWelcome to Alpine Linux 3.18\r\r\r\n...\r\r\r\r\n(domU) + echo 'pci test passed'\r\r\r\r\n(domU) pci test passed\r\r\r\r..." (spawn_id exp4) match regular expression "pci test passed"? Gate "pci test passed"? gate=yes re=yes
    ...
    Gate keeper glob pattern for '\nWelcome to Alpine Linux' is '
    Welcome to Alpine Linux'. Activating booster.
    expect: does "'\r\r\r\r\n(domU) pci test passed\r\r\r\r\n(domU)  [ ok ]\r\r\r\r\n(domU)  [ ok ]\r\r\r\r\n(domU) \r\r\r\r\r\n(domU) domU Welcome to Alpine Linux 3.18\r\r\r\r\n(domU) \rKernel 6.6.56 on an x86_64 (/dev/hvc0)\r\r\r\r\n(domU) \r\r\r\r\r\n" (spawn_id exp4) match regular expression "\nWelcome to Alpine Linux"? Gate "\nWelcome to Alpine Linux"? gate=no

Fix this by using -notransfer flag to keep matched part in the buffer.

Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Acked-by: Andrew Cooper <andrew.cooper3@citix.com>