[11u] RFR(M): 8248190: PPC: Enable Power10 system and use new byte-reverse instructions

[joserz at linux.ibm.com]

Hello team!

I'd like to backport the following patchset to 11u. It doesn't apply perfectly due to some positional changes and a copyright update.
Please, let me know if you prefer another webrev addressing this backport.

Webrev: https://cr.openjdk.java.net/~mhorie/8248190/webrev.02/
Bug: https://bugs.openjdk.java.net/browse/JDK-8248190

Thank you very much,

Jose R Ziviani