Add python_variable._is_view for debugging. (#18197)
Summary:
I don't know if we actually want to expose this or not, but it's useful for debugging.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/18197
Reviewed By: ezyang
Differential Revision: D14530712
Pulled By: gchanan
fbshipit-source-id: 98fdba9cf113738f0db3a198c49365de536b9919
