[vulkan] Clean up deprecated code (#80728)
Part of a refactor of the Vulkan codebase.
Simply removes some parts of the old API and miscellaneous cleanup.
Differential Revision: [D37315038](https://our.internmc.facebook.com/intern/diff/D37315038/)
Pull Request resolved: https://github.com/pytorch/pytorch/pull/80728
Approved by: https://github.com/kimishpatel
