RFR: 8155795: Optimize Integer/Long.reverse by using reverseBytes

[Claes Redestad]

Hi,

I'd like to sponsor this patch proposed by Jaroslav Kameník here: 
http://mail.openjdk.java.net/pipermail/core-libs-dev/2016-April/040660.html

Bug https://bugs.openjdk.java.net/browse/JDK-8155795
Webrev: http://cr.openjdk.java.net/~redestad/8155795/webrev.01/

The idea is that reusing reverseBytes can bring a speedup since this 
method is intrinsified on many platforms.

Thanks!

/Claes