Vulkan: Add flushCommandsAndEndRenderPassWithoutQueueSubmit() Add flushCommandsAndEndRenderPassWithoutQueueSubmit() to allow ContextVk::flushAndGetSerial() to only issue a single vkQueueSubmit(). Bug: angleproject:6546 Change-Id: Ia3fc2bb93e88583ebd80ee153749dc8ca42245dc Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/3200673 Reviewed-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org> Commit-Queue: Tim Van Patten <timvp@google.com>