MdePkg/BaseLib: Break out IA32/X64 GCC inline privileged functions

MdePkg/BaseLib: Break out IA32/X64 GCC inline privileged functions

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=2800

Break out the IA32/X64 GCC inline functions that can not be used
in a unit test host application into their own source file.  This
does not make any changes to the BaseLib library instance.  This
is in preparation for a new BaseLib instances that is safe to use
with host-based unit test applications.

Cc: Liming Gao <liming.gao@intel.com>
Cc: Sean Brogan <sean.brogan@microsoft.com>
Cc: Bret Barkelew <Bret.Barkelew@microsoft.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Signed-off-by: Michael D Kinney <michael.d.kinney@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>