Fix symbolic shape inference for faster_rcnn, mask_rcnn, yolov3 (#1867)
* Fix symbolic shape inference for faster_rcnn, mask_rcnn, yolov3
Force merge when --auto_merge, on symbolic dims which sympy cannot simplify
Add symbolic inference for Resize opset 10
Add support for step != 1 in Slice
Add support for computed dim in TopK
Bug fixes in passing symbolic dims from subgraph
Fix an outdate comment in Nuphar provider header