UefiCpuPkg/CpuMp: Fix hang when StackGuard is enabled in 16-core cpu

UefiCpuPkg/CpuMp: Fix hang when StackGuard is enabled in 16-core cpu

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=3167

When StackGuard is enabled, the CpuMp driver allocates
known good stacks for all CPUs for DF# and PF# exceptions.
It uses AllocatePool to do so.

The size needed equals to 64KB
= StackSize (2K) * ExceptionNumber (2) * NumberOfProcessors (16)

However, AllocatePool max allocation size is less than 64K.
To fix the issue, AllocatePages() is used.

Signed-off-by: Ray Ni <ray.ni@intel.com>
Reviewed-by: Eric Dong <eric.dong@intel.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Cc: Rahul Kumar <rahul1.kumar@intel.com>