Don't release vk memory allocator until context is deleted.

Bug: chromium:1081806

Change-Id: I0a7a92408a3f2119e6b70d8eef6aa4f2d1982d4b
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/297357
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Greg Daniel <egdaniel@google.com>
4 files changed