debug-bp-migration in ubuntu_kvm_unit_tests failed with B-4.15 ARM64 (QEMU Aborted)

[Po-Hsu Lin]

Issue found after kvm-unit-test repo updated to d8a4f9e5 (ci: Update the list of tests that we run in the Fedora Cirrus-CI)

Test failed on ARM64 instance helo-kernel and scobee-kernel with:
Running '/home/ubuntu/autotest/client/tmp/ubuntu_kvm_unit_tests/src/kvm-unit-tests/tests/debug-bp-migration'
 BUILD_HEAD=35a22051
 run_migration timeout -k 1s --foreground 90s /usr/bin/qemu-system-aarch64 -nodefaults -machine virt,gic-version=host -accel kvm -cpu host -device virtio-serial-device -device virtconsole,chardev=ctd -chardev testdev,id=ctd -device pci-testdev -display none -serial stdio -kernel /tmp/tmp.9k8gO78K2x -smp 1 -append bp-migration # -initrd /tmp/tmp.yFQXM3dmKS
 Now migrate the VM, then press a key to continue...
 qemu-system-aarch64: /build/qemu-CSVgGZ/qemu-2.11+dfsg/util/qemu-thread-posix.c:64: qemu_mutex_lock: Assertion `mutex->initialized' failed.
 timeout: the monitored command dumped core
 /tmp/tmp.dZBADK9yI9: line 141: 14478 Aborted timeout -k 1s --foreground 90s /usr/bin/qemu-system-aarch64 -nodefaults -machine virt,gic-version=host -accel kvm -cpu host -device virtio-serial-device -device virtconsole,chardev=ctd -chardev testdev,id=ctd -device pci-testdev -display none -serial stdio -kernel /tmp/tmp.9k8gO78K2x -smp 1 -append bp-migration -initrd /tmp/tmp.yFQXM3dmKS -chardev socket,id=mon2,path=/tmp/mig-helper-qmp2.vPXsRvgomi,server=on,wait=off -mon chardev=mon2,mode=control -incoming unix:/tmp/mig-helper-socket.G8xPpGRaXw
 QEMU Aborted
 FAIL debug-bp-migration (terminated on SIGABRT)