[PT2][Inductor]Add unbind node normalization (#120253)
Summary: Normalize unbind nodes for the followup split_cat pattern detection and node removals
Test Plan:
```
buck2 test //caffe2/test/inductor:split_cat_fx_passes
```
Buck UI: https://www.internalfb.com/buck2/f42297c2-2595-40a2-b270-5cec026f2fe4
Test UI: https://www.internalfb.com/intern/testinfra/testrun/17451448578242323
Network: Up: 132KiB Down: 88KiB (reSessionID-fc725143-317a-42a9-bc7e-0bbab6ef9e5c)
Jobs completed: 27. Time elapsed: 3:09.2s.
Cache hits: 0%. Commands: 1 (cached: 0, remote: 0, local: 1)
Tests finished: Pass 11. Fail 0. Fatal 0. Skip 0. Build failure 0
```
buck2 test mode/opt mode/inplace caffe2/test/inductor/fb:test_split_cat_fx_passes_aten_fb
```
Differential Revision: D53964593
Pull Request resolved: https://github.com/pytorch/pytorch/pull/120253
Approved by: https://github.com/jackiexu1992
