hg: jdk/jdk: 8240588: _threadObj cannot be used on an exiting JavaThread

[david.holmes at oracle.com]

Changeset: 9c608830327b
Author:    dholmes
Date:      2020-05-13 22:29 -0400
URL:       https://hg.openjdk.java.net/jdk/jdk/rev/9c608830327b

8240588: _threadObj cannot be used on an exiting JavaThread
Reviewed-by: rehn, dcubed, kbarrett

! src/hotspot/share/memory/universe.cpp
! src/hotspot/share/prims/whitebox.cpp
! src/hotspot/share/runtime/thread.cpp
! src/hotspot/share/runtime/thread.hpp
! src/hotspot/share/runtime/threadSMR.cpp
! src/hotspot/share/runtime/threadSMR.hpp
+ test/hotspot/jtreg/runtime/Thread/ThreadObjAccessAtExit.java
! test/lib/sun/hotspot/WhiteBox.java