Vulkan: Add support for headless surface How to enable: add below args config to args.gn in linux build ``` use_x11=false use_ozone=false angle_vulkan_display_mode="headless" ``` Bug: angleproject:5260 Change-Id: Iec931e74c061b56376ef028814859aa58af07f2f Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2536518 Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org> Reviewed-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>