remove AutoNonVariableTypeMode guard around forward() call (#28399)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/28399
This is also to address issue #26764
Turns out it's incorrect to wrap the entire forward() call with
NonVariableTypeMode guard as some JIT passes has is_variable() check and
can be triggered within forward() call, e.g.:
jit/passes/constant_propagation.cpp
Since now we are toggling NonVariableTypeMode per method/op call, we can
remove the guard around forward() now.
Test Plan: - With stacked PRs, verified it can load and run previously failed models.
Differential Revision: D18055850
Pulled By: ljk53
fbshipit-source-id: 3074d0ed3c6e05dbfceef6959874e5916aea316c
