Support multiple separator characters, '/' and '\\', on Windows. (#98146)
On Windows, both '/' and '\\' can be used as a path separator, so `StripBasename` should handle them as path separators.
`StripBasename` is used in the `is_enabled` function in `torch\csrc\jit\jit_log.cpp`
Therefore, without this pull request, is_enabled does not work properly on Windows.
For more details, please refer to the issue #98145.
Fixes #98145
Pull Request resolved: https://github.com/pytorch/pytorch/pull/98146
Approved by: https://github.com/ezyang
