[vmap] implement batching rules for clamp, clamp_min and clamp_max (#48449)
Summary:
Fix https://github.com/pytorch/pytorch/issues/47754
- This PR implements batching rules for `clamp`, `clamp_min` and `clamp_max` operators.
- Testcases are added to `test/test_vmap.py`.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/48449
Reviewed By: ejguan
Differential Revision: D25219360
Pulled By: zou3519
fbshipit-source-id: 0b7e1b00f5553b4578f15a6cc440640e506b4918
