Review request (S): 7179517 Enable NUMA by default on NUMA hardware

[Jesper Wilhelmsson]

Hi,

This change is to turn on UseNUMA per default on NUMA hardware. It has been 
contributed by Eric Caspole. I'm fine with the change but we need at least one 
official reviewer.

Webrev:
http://cr.openjdk.java.net/~jwilhelm/7179517/webrev/

Testing:
I ran it through JPRT and did some local sanity testing.
Eric has tested this on SPECjbb2005 and SPECjvm2008 with a variety of heap 
sizes and it is never worse than the current default. In some cases, 
especially with Windows, running a test with the current default and getting 
bad NUMA placement will be about 3x slower than the +UseNUMA score.

The performance team are involved to perform some larger scale testing.