Add static_runtime::fused_equally_split (#2)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch-canary/pull/2
Pull Request resolved: https://github.com/pytorch/pytorch/pull/66881
Adds `static_runtime::fused_equally_split` operator and removes `is_fused` logic from original operator. Modifies `FuseUnpackListV2` to map `fb::equally_split` to this new operator.
Test Plan:
```
adityapillai@5960 /data/sandcastle/boxes/fbsource/fbcode 1m 13s
❯ buck test //caffe2/benchmarks/static_runtime/fb:test_fb_operators
```
and sandcastle
strange_what_could_go_wrong
Reviewed By: mikeiovine
Differential Revision: D31742293
fbshipit-source-id: 60b35589c8817719b005d49811f575b6590d1c39
