[ONNX] Fix for random generators export (#33789)
Summary:
Export random generator with dynamic input size
Pull Request resolved: https://github.com/pytorch/pytorch/pull/33789
Reviewed By: hl475
Differential Revision: D20121175
Pulled By: houseroad
fbshipit-source-id: c16d11eb07678166d125759d97aadfcd7c80ef14
