[API Compatibility] Support ChangePrefixMatcher for aligned nn classes -part (#79539)

* [API Compatibility] Add torch-style aliases for aligned nn classes, Add AvgPool, BatchNorm, and MultiheadAttention aliases to paddle.nn so enable_compat(level=2) can dispatch ChangePrefixMatcher outputs to their compat implementations.

* Add seven api to __all__ per reviewer suggestion

* add fix for Tensor.split

* Align 24 compat APIs with PyTorch semantics

* revert to 0d4cb16

* Simplify ForbidKeywordsDecorator and align Tensor.split in api, not in separate logic