hg: jdk/hs: 8129440: G1 crash during concurrent root region scan

[thomas.schatzl at oracle.com]

Changeset: 2569f227ae8e
Author:    tschatzl
Date:      2018-01-11 11:28 +0100
URL:       http://hg.openjdk.java.net/jdk/hs/rev/2569f227ae8e

8129440: G1 crash during concurrent root region scan
Summary: Make concurrent memory accesses to oops on the heap volatile to avoid reloading by the compiler duplicating oop loading code.
Reviewed-by: ehelin, eosterlund

! src/hotspot/share/gc/g1/g1OopClosures.inline.hpp