MdePkg/Test/BaseLib: Add SAFE_STRING_CONSTRAINT_CHECK unit test

MdePkg/Test/BaseLib: Add SAFE_STRING_CONSTRAINT_CHECK unit test

Use the safe string function StrCpyS() in BaseLib to test the
SAFE_STRING_CONSTRAINT_CHECK() macro.

Cc: Andrew Fish <afish@apple.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Bret Barkelew <bret.barkelew@microsoft.com>
Cc: Brian J. Johnson <brian.johnson@hpe.com>
Cc: Chasel Chiu <chasel.chiu@intel.com>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Leif Lindholm <leif@nuviainc.com>
Cc: Liming Gao <liming.gao@intel.com>
Cc: Marvin Häuser <mhaeuser@outlook.de>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Vincent Zimmer <vincent.zimmer@intel.com>
Cc: Zhichao Gao <zhichao.gao@intel.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Vitaly Cheptsov <vit9696@protonmail.com>
Signed-off-by: Michael D Kinney <michael.d.kinney@intel.com>
Reviewed-by: Philippe Mathieu-Daude <philmd@redhat.com>
Reviewed-by: Vitaly Cheptsov <vit9696@protonmail.com>
Acked-by: Liming Gao <liming.gao@intel.com>