Revert D23252335: Refactor Vulkan context into its own files. Use RAII.
Test Plan: revert-hammer
Differential Revision:
D23252335 (https://github.com/pytorch/pytorch/commit/054073c60d066a7f2e6d2eca69fba52760c43544)
Original commit changeset: 43144446f2f3
fbshipit-source-id: 442b914f47a82efee18cfd84aab893e22d1defdd