move import_class_test files around (#26722)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/26722
Put them in a directory under jit/ to prep for test splitting
Test Plan: Imported from OSS
Differential Revision: D17550582
Pulled By: suo
fbshipit-source-id: a592b671ffe808f02d0a597d441bd98a18c9109e
