UefiCpuPkg/MpInitLib: increase NumApsExecuting only for ApInitConfig

UefiCpuPkg/MpInitLib: increase NumApsExecuting only for ApInitConfig

NumApsExecuting is only used when InitFlag == ApInitConfig for
counting the processor count.

The patch changes Ia32 version of waking up vector assembly code
to align to x64 version of waking up vector assembly code.
After the change both versions of waking up vector increase
NumApsExecuting when InitFlag == ApInitConfig.

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