Vulkan: Apply point size clamping workaround in NV. It seems to be a regression in recent drivers. Olli contributed this workaround for the GL back-end some time ago. This CL enables it for Vulkan as well on the affected drivers. Bug: angleproject:2970 Change-Id: I37f0caf8d9db073cb880aa1500d1ff7a1eee9d34 Reviewed-on: https://chromium-review.googlesource.com/c/1341108 Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Jamie Madill <jmadill@chromium.org>