[ET-VK] Move `save_cache` from Runtime dtor to model destroy

[pytorchbot]

This PR was created by the merge bot to help merge the original PR into the main branch. ghstack PR number: https://github.com/pytorch/executorch/pull/6974 ^ Please use this as the source of truth for the PR details, comments, and reviews ghstack PR base: https://github.com/pytorch/executorch/tree/gh/jorgep31415/126/base ghstack PR head: https://github.com/pytorch/executorch/tree/gh/jorgep31415/126/head Merge bot PR base: https://github.com/pytorch/executorch/tree/gh/jorgep31415/125/orig Merge bot PR head: https://github.com/pytorch/executorch/tree/gh/jorgep31415/126/orig @diff-train-skip-merge

[pytorch-bot[bot]]

:link: Helpful Links

:test_tube: See artifacts and rendered test results at hud.pytorch.org/pr/pytorch/executorch/7002

• :page_facing_up: Preview Python docs built from this PR

Note: Links to docs will display an error until the docs builds have been completed.

:heavy_exclamation_mark: 1 Active SEVs

There are 1 currently active SEVs. If your PR is affected, please view them below:

• [DomainsOnly] Jobs fail with GLIBC version not found

:white_check_mark: No Failures

As of commit 8f4edae39d027b1c161332b85f9bbca57fb120a2 with merge base 711f1c23d32acd798dabf0028b31e8fcb2c2487f (): :green_heart: Looks good so far! There are no failures yet. :green_heart:

This comment was automatically generated by Dr. CI and updates every 15 minutes.