[C++ API] Allow skipping default arguments in module's forward method when module is used in Sequential (#33027)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/33027
This PR allows default arguments in module's forward method to be skipped when module is used in `torch::nn::Sequential`, by introducing the `FORWARD_HAS_DEFAULT_ARGS` macro and requiring that all modules that have default arguments in its forward method must have a corresponding `FORWARD_HAS_DEFAULT_ARGS` macro call.
Fixes issue mentioned in https://github.com/pytorch/pytorch/issues/30931#issuecomment-564144468.
Test Plan: Imported from OSS
Differential Revision: D19777815
Pulled By: yf225
fbshipit-source-id: 73282fcf63377530063e0092a9d84b6c139d2e32
