git: openjdk/jdk: 8259668: Make SubTasksDone use-once

[Thomas Schatzl]

Changeset: 3cbd16de
Author:    Albert Mingkun Yang <ayang at openjdk.org>
Committer: Thomas Schatzl <tschatzl at openjdk.org>
Date:      2021-02-16 08:46:58 +0000
URL:       https://git.openjdk.java.net/jdk/commit/3cbd16de

8259668: Make SubTasksDone use-once

Reviewed-by: tschatzl, kbarrett

! src/hotspot/share/gc/g1/g1RootProcessor.cpp
! src/hotspot/share/gc/shared/workgroup.cpp
! src/hotspot/share/gc/shared/workgroup.hpp
! src/hotspot/share/runtime/safepoint.cpp