Vulkan: Fix serial mismatch during mid-loop flush Currently, if the total buffer updates to the image surpasses a certain threshold, it results in a flush. However, this can cause discrepencies in the queue serial, which can result in incorrect behavior on some platforms. * Updated flushStagedUpdatesImpl() so that the image serial after applying the updates matches that of the current outside command buffer. * That includes when there is a flush in the middle of the update loop, resulting in submission and new queue serial for the CB. * Added a unit test to check if a large texture can uploaded and deleted after a second small texture is uploaded. * Texture1UploadThenTexture2UploadThenTexture1Delete * Added a unit test for flushing when uploading cubemap textures. Bug: b/351650806 Bug: b/356192937 Change-Id: I7f9b20e4b7fd49115f22081a9733b4d44b740e4a Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/5744377 Commit-Queue: Amirali Abdolrashidi <abdolrashidi@google.com> Reviewed-by: Charlie Lao <cclao@google.com> Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>