New support for resize op (onnx#844)

* shape inference for size

Signed-off-by: Tong Chen <[email protected]>

* to Krnl

Signed-off-by: Tong Chen <[email protected]>

* change constant

Signed-off-by: Tong Chen <[email protected]>

* add backend test

Signed-off-by: Tong Chen <[email protected]>

* change check lit

Signed-off-by: Tong Chen <[email protected]>

Co-authored-by: Tung D. Le <[email protected]>

Use DenseElementAttr instead of StringRef for constants (onnx#639)

* try DenseElementAttr

Signed-off-by: Kevin O'Brien <[email protected]>

* remove lit tests

Signed-off-by: Kevin O'Brien <[email protected]>

* go back to StringAttr

Signed-off-by: Kevin O'Brien <[email protected]>

* determine Attr type based on size

Signed-off-by: Kevin O'Brien <[email protected]>

* fix type

Signed-off-by: Kevin O'Brien <[email protected]>