hg: panama/dev: Fix int64 max reduction

[razvan.a.lupusoru at intel.com]

Changeset: 7ddbaf84e004
Author:    rlupusoru
Date:      2018-05-31 17:56 -0700
URL:       http://hg.openjdk.java.net/panama/dev/rev/7ddbaf84e004

Fix int64 max reduction

! src/hotspot/cpu/x86/x86.ad