hg: jdk/jdk: 8243326: Cleanup use of volatile in taskqueue code

[kim.barrett at oracle.com]

Changeset: 252a1602b4c6
Author:    kbarrett
Date:      2020-04-14 02:25 -0400
URL:       https://hg.openjdk.java.net/jdk/jdk/rev/252a1602b4c6

8243326: Cleanup use of volatile in taskqueue code
Summary: Removed volatile on queue elements, cleaned up other uses, made atomics explicit.
Reviewed-by: tschatzl, iwalulya

! src/hotspot/share/gc/g1/g1ConcurrentMark.hpp
! src/hotspot/share/gc/shared/taskqueue.hpp
! src/hotspot/share/gc/shared/taskqueue.inline.hpp