Codegen: TraceType only includes operators being registered (#68691)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/68691
TraceType is a sharded file, so by only including specific operator
headers, we ensure that changing one (non-method) operator only needs
one shard to be re-compiled.
This also changes all the included autograd and jit headers from
including `ATen/ATen.h` to just including `ATen/core/Tensor.h`.
Test Plan: Imported from OSS
Reviewed By: gchanan
Differential Revision: D33336948
Pulled By: albanD
fbshipit-source-id: 4e40371592b9a5a7e7fcd1d8cecae11ffb873113
