SWDEV-510319 - Fixed random segfaults in graph tests

This change fixes random segfaults in graph tests that
are seen after the change make internal callbacks non-blocking.
The callback thread that decreases the GraphExec ref count
may now run after the runtime shutdown. This can cause a segfault
because the hip::device that is accessed in GraphExec destructor
is already destroyed during runtime shutdown. This patch ensures
that the hip::device object  stays alive until after the
callback thread completes.

Change-Id: I75a6ac01f27a0b2250bbd10ed389ebfb322927af

hipamd/src/hip_graph_internal.cpp

@@ -363,6 +363,7 @@ hipError_t GraphExec::Init() {
     status = CaptureAQLPackets();
   }
   instantiateDeviceId_ = hip::getCurrentDevice()->deviceId();
+  static_cast<ReferenceCountedObject*>( hip::getCurrentDevice())->retain();
   return status;
 }