This patch adds two tests for replaying Linux boot process
on x86_64 virtio platform.

Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgalyuk@ispras.ru>
Message-Id: <165364840811.688121.11931681195199516354.stgit@pasha-ThinkPad-X280>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>