Vulkan: Store fences instead of serials in SurfaceVK::SwapHistory Previous swaps may not have been submitted by the same context as the current swap and we can't safely wait on serials submitted by other contexts. BUG=angleproject:2464 Change-Id: Ibcb23171feae038fd45abdefb80c4e8a373744e2 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1562521 Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org> Commit-Queue: Geoff Lang <geofflang@chromium.org>