Don't attempt to collect "profile" counters (instructions retired, etc.) unless running on Win8 or greater. This also fixes a problem with the way we were detecting Win8 previously. Fixes #105.
Don't attempt to collect "profile" counters (instructions retired, etc.) unless running on Win8 or greater.
This also fixes a problem with the way we were detecting Win8 previously.
Fixes #105.

visia/xunit-performance,pharring/xunit-performance,Microsoft/xunit-performance,ericeil/xunit-performance,Microsoft/xunit-performance