message: cuda: avoid unnecessary cudaStreamSynchronize() call
  resolves
diff: @@ -594,11 +594,12 @@ namespace
  StackAllocator::~StackAllocator()
  {
  - cudaStreamSynchronize(stream_);
  -
  if (memStack_ != 0)
  + {
  + cudaStreamSynchronize(stream_);
  memStack_->pool->returnMemStack(memStack_);
  }
  + }
  size_t alignUp(size_t what, size_t alignment)
  {
  