[aarch64-port-dev ] Backport patches for 8031818, 8139758 and 8144993

[Felix Yang]

Hi,

  Please review: http://cr.openjdk.java.net/~fyang/8u-backports/webrev/

  This backport three patchs: 8031818, 8139758 and 8144993 to jdk8u aarch64
port.
  I think It's necessary for this repo to have the last two patches.  I
backport the first one as the second one depends on it.
  We see some performance gain for one of our real world Java application.
  Tested with JTreg on aarch64 Linux platform, OK to push?

Felix,
Thanks