Migration tests should only migrate servers to hypervisors of the
same type (e.g., QEMU to QEMU, not QEMU to Ironic). This prevents
test failures in mixed hypervisor environments.
Updated both scenario and functional migration tests to filter
candidate hypervisors by hypervisor_type before selecting a
migration target.
Story: 2011623
Task: 53248
Assisted-By: Claude Code/claude-4.5-sonnet
Change-Id: Ic661100db6d22a1528aeb2c69ef95f8f686e60aa
Signed-off-by: Harald Jensås <hjensas@redhat.com>