[8u] RFA JDK-8158012: Use SW prefetch instructions instead of BIS for allocation prefetches on SPARC Core C4

[Muthusamy Chinnathambi]

Hi,

May I get the approval of backport of 'JDK-8158012: Use SW prefetch instructions instead of BIS for allocation prefetches on SPARC Core C4' to jdk8u.

Jdk9 bug: https://bugs.openjdk.java.net/browse/JDK-8158012
Jdk9 review thread: http://mail.openjdk.java.net/pipermail/hotspot-compiler-dev/2016-December/025089.html
Jdk8 review thread: http://mail.openjdk.java.net/pipermail/hotspot-dev/2017-July/027561.html
                                    http://mail.openjdk.java.net/pipermail/hotspot-dev/2017-August/028107.html
Enhancement request approval thread: http://mail.openjdk.java.net/pipermail/jdk8u-dev/2017-August/006880.html
                                                                        http://mail.openjdk.java.net/pipermail/jdk8u-dev/2018-April/007392.html

Regards,
Muthusamy C