JVM crash in RootsClosure

Issue

• An application making heavy use of JNI code crashes when gc code iterates over JNI handles due to an address that does not exist in the application address space.
• Shenandoah GC:

Stack: [0x00007f9a983e4000,0x00007f9a984e4000],  sp=0x00007f9a984e2b90,  free space=1018k
Native frames: (J=compiled Java code, A=aot compiled Java code, j=interpreted, Vv=VM code, C=native code)
V  [libjvm.so+0xd56be4]  ShenandoahInitMarkRootsClosure<(UpdateRefsMode)0>::do_oop(oopDesc**)+0x34
V  [libjvm.so+0x94c826]  JNIHandles::oops_do(OopClosure*)+0x86
V  [libjvm.so+0xd91fd3]  ShenandoahSerialRoot::oops_do(OopClosure*, unsigned int)+0x83
V  [libjvm.so+0xd6e30c]  ShenandoahRootScanner<ShenandoahAllCodeRootsIterator>::roots_do(unsigned int, OopClosure*, CLDClosure*, CodeBlobClosure*, ThreadClosure*)+0xbc
V  [libjvm.so+0xd6e53d]  ShenandoahInitMarkRootsTask<(UpdateRefsMode)0>::work(unsigned int)+0x12d
V  [libjvm.so+0xefa38d]  GangWorker::loop()+0x5d
V  [libjvm.so+0xe6680c]  Thread::call_run()+0x15c
V  [libjvm.so+0xc1cc86]  thread_native_entry(Thread*)+0xf6

• Parallel GC:

Stack: [0x00007f73a4785000,0x00007f73a4885000],  sp=0x00007f73a4883bb0,  free space=1018k
Native frames: (J=compiled Java code, A=aot compiled Java code, j=interpreted, Vv=VM code, C=native code)
V  [libjvm.so+0xc9454e]  oopDesc* PSPromotionManager::copy_to_survivor_space<false>(oopDesc*)+0x14e
V  [libjvm.so+0xc987bc]  PSRootsClosure<false>::do_oop(oopDesc**)+0x6c
V  [libjvm.so+0x94a706]  JNIHandles::oops_do(OopClosure*)+0x86
V  [libjvm.so+0xc98bb9]  ScavengeRootsTask::do_it(GCTaskManager*, unsigned int)+0x109
V  [libjvm.so+0x7f5a49]  GCTaskThread::run()+0x209
V  [libjvm.so+0xe58818]  Thread::call_run()+0x158
V  [libjvm.so+0xc11926]  thread_native_entry(Thread*)+0xe6