[8u40] RFR(S): Set T family feature bit on Niagara systems

[Mikael Vidstedt]

Please review this 8u40 backport request. The fix was pushed to jdk9 a 
couple of weeks ago and has not shown any problems.

The change from jdk9 applies to jdk8u/hs-dev without conflicts.

Bug: https://bugs.openjdk.java.net/browse/JDK-8046769
Webrev: 
http://cr.openjdk.java.net/~mikael/webrevs/8046769/webrev.00/webrev/
jdk9 change: 
http://hg.openjdk.java.net/jdk9/hs-comp/hotspot/rev/2399ebcea84d

Thanks,
Mikael