[NtQuerySystemInformation #1] Fixes + tests

[Paul Vriens]

Hi,

this is a first go at some unit tests and related fixes for
NtQuerySystemInformation.

The ultimate goal is to get SysInternal's Process Explorer running.

I welcome suggestions and remarks. If none I will submit this to
wine-patches and start the further works.

Cheers,

Paul Vriens.

Changelog
  Start of unit tests for NtQuerySystemInformation
  Return STATUS_INVALID_INFO_CLASS for non-implemented classes
  Return len for SystemCpuInformation
  Return STATUS_ACCESS_VIOLATION if no buffer given