Dynamo+LTC: merging related code from staging branch to master (#75046)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/75046
Merge the code needed for dynamic+ltc integration from the staging branch to the master branch.
Test Plan:
Unit test
```
pytest test_extract_compiled_graph
```
test thru dynamo
```
LTC_TS_CUDA=1 time python torchbench.py --speedup-ltc -dcuda --nvfuser --randomize-input --only <model name>
```
Reviewed By: alanwaketan
Differential Revision: D35300646
Pulled By: shunting314
fbshipit-source-id: 09ed20d3bb8ef80e4b93ba87ea3356a07d2dccdb
(cherry picked from commit 2b56771cdfd2cfa825c65ee9fd42338fb372fb32)
