[webgpu] Support int64 for range

[qjia7]

Needed by updating position id with an onnx model in genai.

Continuous decoding mode: position_ids[i] = i + total_length - new_kv_length

We can use an onnx model which includes a Range op to implement update the position ids:
Inputs: start (total_length - new_kv_length), limit (total_length), delta (1)
Output: position_ids (1D tensor of size new_kv_length)