[8u] RFR: 8191955: AArch64: incorrect prefetch distance causes an internal error

[Guo Ge]

Hi,

I would like to request a review for backport of JDK-8191955.

Original bug: https://bugs.openjdk.java.net/browse/JDK-8191955
webrev for 8u: http://cr.openjdk.java.net/~gguo/8191955-8u/webrev.00/

The original fix is not clean due to context change, `java 
-XX:AllocatePrefetchDistance=196 -jar SPECjvm2008.jar -coe -ikv -wt 5s 
-it 10s scimark.sparse.large` will throw a crash without the patch and 
pass with it.

Thanks,
Guo Ge