qemu.tests: new case for timedrift testing

changes from V1:
    1. fix typo and update doc strings

Signed-off-by: Xu Tian <xutian@redhat.com>
qemu.tests: configuration for new timedrift testing

Signed-off-by: Xu Tian <xutian@redhat.com>
shared.deps: script to adjust host/guest time

Signed-off-by: Xu Tian <xutian@redhat.com>