Vulkan: Enable FenceNV extension without graph. Bug: angleproject:4029 Change-Id: I6b3f469b692010e373b9c82b689966da98b8a6cc Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2065918 Reviewed-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Courtney Goeltzenleuchter <courtneygo@google.com> Commit-Queue: Jamie Madill <jmadill@chromium.org>