This partially reverts commit 905ee082
due to regression caused on startup time.

Instead of calling finish before destroying the context, the objects in
the Vulkan backend are `release()`ed instead of `destroy()`ed, so they
will be kept alive for the duration of current work.

Bug: 904846
Change-Id: Ia774470666c4c0d4c1ddc348f685d621243de204
Reviewed-on: https://chromium-review.googlesource.com/c/1333969Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>