[inductor] Support complex fallback for convert_element_type, _fft_c2c, view_as_real to support GoogleFnet with cpp wrapper (#103183)
Fixes #102752
These 3 fallback kernels appear in GoogleFnet because they take complex arguments - i.e., usually they aren't fallback kernels. To support this model, we added support for these 3 ops.
Details:
1. Add these 3 ops to the allowlist. I assume that we eventually want to support all fallback kernels, but for now we just add these 3 ops to the allowlist.
2. Support complex64 in cpp codegen
3. Support List[] arguments and ScalarType arguments in cpp codegen
4. Allow alias_info in schema arguments. In the original PR supporting fallback kernels for cpp wrapper, ops with schemas with non-null alias_info for any of the arguments were disallowed; but I don't think there's any reason we need to disallow these in cpp wrapper code.
Caveats:
* This has not added support for complex32 or complex128
* It only works with static shapes, not dynamic shapes. It seems like the dynamic shapes issue is unrelated to cpp wrapper, since it fails in the test_torchinductor_dynamic_shapes.py test. I checked these `test_fft_.*` tests, which I added in this PR, and verified that they were broken with dynamic shapes before any of the code changes from this PR.
**Test**:
```
benchmarks/dynamo/huggingface.py --inductor --amp --accuracy --inference --device cuda --cpp-wrapper --only GoogleFnet
```
Pull Request resolved: https://github.com/pytorch/pytorch/pull/103183
Approved by: https://github.com/desertfire, https://github.com/jgong5, https://github.com/chunyuan-w
