Fix some incorrect annotations found by clang-cl (#35364)
Summary:
Fixes incorrect usages of symbol annotations including:
1. Exporting or importing a function/class in an anonymous namespace.
2. Exporting or importing a function/class implementation in a header file. However, by removing the symbol annotations, they are now local symbols. If they need to be remain global, I can move the implementations to the source file.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/35364
Differential Revision: D20670031
Pulled By: ezyang
fbshipit-source-id: cd8018dee703e2424482c27fe9608e040d8105b8
