Update jvp to support symbolic execution. (#120338)
Previously, all jvp tests under dynamo/test_dynamic_shapes would fail because symbolic execution wasn't supported in some autograd functions.
List of changes:
- Update`_has_same_storage_numel` to use `sym_nbytes`
- Symintify `_efficientzerotensor_meta`
- Introduce `empty_generic_symint` with the first argument `size` as symbolic integer
- Update gen_variable_type.py script to call the symint version of zeros_fn function (zeros_symint / _efficientzerotensor_symint)
- Update `has_same_meta` to call `sym_*` functions
Pull Request resolved: https://github.com/pytorch/pytorch/pull/120338
Approved by: https://github.com/soulitzer
ghstack dependencies: #119926
