Don't submit vk command buffer in updateBackendTexture.

So apparently I did all the work to allow us to not submit in
updateBackendTexture, but then I never actually removed the submit...

Bug: chromium:1087124
Change-Id: Id08a9c5e116cff57dbbeada74186f94da6e28656
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/297866
Commit-Queue: Greg Daniel <egdaniel@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
5 files changed