[WIP][JIT] Opinfo test for nnc fusion
These tests check to ensure that
(a) the result after nnc fusion (of a single op) is the same as the
unfused op
(b) for certain ops where fusion is expected to occur, ensure that
fusion does actually occur
ghstack-source-id: 6ad8a8229581b0545db1590401f435b141804265
Pull Request resolved: https://github.com/pytorch/pytorch/pull/70465
