ProcessorCount: Fix virtual processor count on Solaris

The previous code did not count the number of virtual processors across physical processors on SunOS.

Can handle the following situations:

$ uname -a
SunOS solaris 5.11 11.4.0.15.0 i86pc i386 i86pc
$ psrinfo -p -v
The physical processor has 1 virtual processor (0)
  x86 (GenuineIntel 306D2 family 6 model 61 step 2 clock 3492 MHz)
        Intel Core Processor (Broadwell)
The physical processor has 1 virtual processor (1)
  x86 (GenuineIntel 306D2 family 6 model 61 step 2 clock 3492 MHz)
        Intel Core Processor (Broadwell)
The physical processor has 1 virtual processor (2)
  x86 (GenuineIntel 306D2 family 6 model 61 step 2 clock 3492 MHz)
        Intel Core Processor (Broadwell)
The physical processor has 1 virtual processor (3)
  x86 (GenuineIntel 306D2 family 6 model 61 step 2 clock 3492 MHz)
        Intel Core Processor (Broadwell)

$ uname -a
SunOS sol11x86 5.11 11.0 i86pc i386 i86pc
$ psrinfo -p -v
The physical processor has 2 virtual processors (0 1)
  x86 (GenuineIntel 50650 family 6 model 85 step 0 clock 2000 MHz)
        Intel(r) Xeon(r) Gold 6138 CPU @ 2.00GHz

$ uname -a
SunOS sol11 5.11 11.0 sun4v sparc sun4v
$ psrinfo -p -v
The physical processor has 2 cores and 16 virtual processors (0-15)
  The core has 8 virtual processors (0-7)
  The core has 8 virtual processors (8-15)
    SPARC-T4 (chipid 0, clock 2848 MHz)

Topic-rename: ProcessorCount-solaris