[jit] Better match behavior of loaded ScriptModules vs. freshly created ones (#43298)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/43298
IR emitter uses `ModuleValue` to represent ScriptModules and emit IR for
attribute access, submodule access, etc.
`ModuleValue` relies on two pieces of information, the JIT type of the
module, and the `ConcreteModuleType`, which encapsulates Python-only
information about the module.
ScriptModules loaded from a package used to create a dummy
ConcreteModuleType without any info in it. This led to divergences in
behavior during compilation.
This PR makes the two ways of constructing a ConcreteModuleType equivalent,
modulo any py-only information (which, by definition, is never present in
packaged files anyway).
Test Plan: Imported from OSS
Reviewed By: bertmaher
Differential Revision: D23228738
Pulled By: suo
fbshipit-source-id: f6a660f42272640ca1a1bb8c4ee7edfa2d1b07cc
