RFR(S): 8158012: Use SW prefetch instructions instead of BIS for allocation prefetches on SPARC Core S4

[Shrinivas Joshi]

Hi,

Please review this small change which sets the default allocation 
prefetch mechanism on Oracle SPARC Core S4 processor based systems to 
use explicit SW prefetch instructions instead of Block Init Store(BIS) 
instructions.

Bug: http://bugs.openjdk.java.net/browse/JDK-8158012
Webrev: http://cr.openjdk.java.net/~kvn/8158012/webrev.00/

Tested with JTREG and JPRT.

Thanks,
-Shrinivas