hg: jdk/sandbox: 8226228: Make Threads_lock an always safepoint checked lock.

[chris.hegarty at oracle.com]

Changeset: 4aea554692aa
Author:    rehn
Date:      2019-08-09 11:04 +0200
URL:       https://hg.openjdk.java.net/jdk/sandbox/rev/4aea554692aa

8226228: Make Threads_lock an always safepoint checked lock.
Reviewed-by: coleenp, dcubed, dholmes

! src/hotspot/share/jfr/periodic/sampling/jfrThreadSampler.cpp
! src/hotspot/share/prims/jni.cpp
! src/hotspot/share/runtime/handshake.cpp
! src/hotspot/share/runtime/mutex.cpp
! src/hotspot/share/runtime/mutexLocker.cpp
! src/hotspot/share/runtime/thread.cpp
! src/hotspot/share/runtime/thread.hpp
! src/hotspot/share/runtime/threadSMR.cpp
! src/hotspot/share/runtime/vmOperations.cpp
! src/hotspot/share/utilities/vmError.cpp