UefiCpuPkg/PiSmmCpuDxeSmm: Implement NULL pointer detection for SMM code

UefiCpuPkg/PiSmmCpuDxeSmm: Implement NULL pointer detection for SMM code

The mechanism behind is the same as NULL pointer detection enabled in EDK-II
core. SMM has its own page table and we have to disable page 0 again in SMM
mode.

Cc: Star Zeng <star.zeng@intel.com>
Cc: Eric Dong <eric.dong@intel.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Michael Kinney <michael.d.kinney@intel.com>
Cc: Ayellet Wolman <ayellet.wolman@intel.com>
Suggested-by: Ayellet Wolman <ayellet.wolman@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Jian J Wang <jian.j.wang@intel.com>
Reviewed-by: Star Zeng <star.zeng@intel.com>
Reviewed-by: Eric Dong <eric.dong@intel.com>