fix double free in test_jit (#18121)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/18121
ghimport-source-id: 70c273bfbcb68f7b25cf87f5614c662960864758
Stack from [ghstack](https://github.com/ezyang/ghstack):
* **#18121 [jit] fix double free in test_jit**
These definitions used to be in anonymous namespace so they weren't exported from the translation unit. #18071 put those in a `test` namespace so I guess they were getting their destructors called twice on exit somehow. Making them static again fixes the problem.
Reviewed By: ezyang
Differential Revision: D14498349
fbshipit-source-id: f969781695dcbebdfcfce667fce5b986222a373e
