Vulkan: Track used Images in RenderPass. Adding a simple ImageSerial tracking map in our RenderPass allows us to know when we do or do not need to close the RenderPass on a new Image access. This simple tracking scheme improves Manhattan performance by up to 25% on Android. The improved perf comes from reducing our RenderPass count (23->18 RenderPasses in our capture scene). Adds a FastUnorderedSet class to manage the used RP Image serials. Updates the Query helpers to explicitly flush the RP before inserting queries. Bug: angleproject:4911 Change-Id: I0c34fc8e307514ebdf3e81e08d8e5aedb70ebe8f Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2334346 Reviewed-by: Charlie Lao <cclao@google.com> Reviewed-by: Tim Van Patten <timvp@google.com> Commit-Queue: Jamie Madill <jmadill@chromium.org>