Refine test case: 1. Check PAE paging reserved bits is zero. 2. Set stack as random value. Reviewed-by: Ray Ni <ray.ni@intel.com> Cc: Rahul Kumar <rahul1.kumar@intel.com> Cc: Gerd Hoffmann <kraxel@redhat.com> Cc: Laszlo Ersek <lersek@redhat.com> Signed-off-by: Zhiguang Liu <zhiguang.liu@intel.com>