8340401: DcmdMBeanPermissionsTest.java and SystemDumpMapTest.java fail with assert(_stack_base != nullptr) failed: Sanity check

src/hotspot/share/nmt/memMapPrinter.cpp

@@ -172,7 +172,7 @@ static bool vma_touches_thread_stack(const void* from, const void* to, const Thr
   // Very rarely however is a VMA backing a thread stack folded together with another adjacent VMA by the
   // kernel. That can happen, e.g., for non-java threads that don't have guard pages.
   // Therefore we go for the simplest way here and check for intersection between VMA and thread stack.
-  return range_intersects(from, to, (const void*)t->stack_end(), (const void*)t->stack_base());
+  return range_intersects(from, to, (const void*)t->stack_end(), (const void*)t->stack_base_or_null());
 }
 
 struct GCThreadClosure : public ThreadClosure {

src/hotspot/share/runtime/thread.hpp

@@ -525,6 +525,7 @@ class Thread: public ThreadShadow {
  public:
   // Stack overflow support
   address stack_base() const DEBUG_ONLY(;) NOT_DEBUG({ return _stack_base; })
+  address stack_base_or_null() const   { return _stack_base; }
   void    set_stack_base(address base) { _stack_base = base; }
   size_t  stack_size() const           { return _stack_size; }
   void    set_stack_size(size_t size)  { _stack_size = size; }