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>