[pytorch][codegen] migrate gen_annotated_fn_args.py to new codegen model (#47745)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/47745
This is a relatively small codegen. Reintroduced 'simple_type' to preserve
old codegen output.
It depends on some methods defined in gen_python_functions.py - next PR will
clean up the remaining Declarations.yaml methods in gen_python_functions.py.
Confirmed byte-for-byte compatible with the old codegen:
```
Run it before and after this PR:
.jenkins/pytorch/codegen-test.sh <baseline_output_dir>
.jenkins/pytorch/codegen-test.sh <test_output_dir>
Then run diff to compare the generated files:
diff -Naur <baseline_output_dir> <test_output_dir>
```
Differential Revision: D24885068
Test Plan: Imported from OSS
Reviewed By: ezyang
Pulled By: ljk53
fbshipit-source-id: c0fbd726bcc450c3c7fe232c23e5b31779d0b65f
