Vulkan: Enable SyncVal for VkEvent based barriers Previously SyncVal is disabled due to some tests time out when VkEvent is enabled. Now with earlier CLs that reduces number of VkEvents being used, we are able to enable SyncVal again when event based barriers are enabled. Bug: b/336844257 Change-Id: Idb4f8646495cd087d79f2d09cd12fccfa9062792 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/5597733 Commit-Queue: Charlie Lao <cclao@google.com> Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org> Reviewed-by: Amirali Abdolrashidi <abdolrashidi@google.com>