[DRLVM][PORT] correct API to retrieve processor number

[Xiao-Feng Li]

Hi, I am using port_CPUs_number() for GCv5 to get the processor
number, but my desktop returns one processor with it on Windows
although my processor is dual-core. (port_CPUs_number is defined in
port_sysinfo.h).

I think we need more general form of processor number retrieval API
that can return processor information including that of core and
hyperthreading.

How do you think?

Thanks,
xiaofeng