The assert in SemaphoreVk::wait() was verifying that acquired images
don't have any staged updates. That assert was failing for images with
emulated image formats, which may have staged updates to clear the image
after initialization.

Bug: chromium:1096746
Change-Id: I74658a8ae48e6c09aa4a859ceb1e2a7099e021c0
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2427551Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Michael Spang <spang@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>