Split ConcreteModuleType into two types (#29824)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/29824
We have two distinct phases/uses for ConcreteModuleType:
1. We are building it up and using it to check whether we can
reuse JIT types. (RawConcreteModuleType)
2. We are using it to satisfy ModuleValue::attr queries.
(ConcreteModuleType)
These types share an underlying `ConcreteModuleTypeData` which
actually stores the relevant info.
Previously they were the same type because I was lazy, but it's been the
source of a bug. So split them to formalize the differing invariants for
the two phases.
Test Plan: Imported from OSS
Differential Revision: D18575010
Pulled By: suo
fbshipit-source-id: 3e4ebcd36e78b947150d8f0dbb74ecccad23e7c4
