This is a reland of a7bb6a9b

Original change's description:
> Add support for Linux vulkan backend with VK_KHR_display
>
> Implement Linux simple display mode with vulkan backend
> through VK_KHR_display.
>
> Added value 'EGL_PLATFORM_VULKAN_DISPLAY_MODE_SIMPLE_ANGLE' for
> attribute EGL_PLATFORM_ANGLE_NATIVE_PLATFORM_TYPE_ANGLE to identify
> the new simple display mode. Also reserved
> EGL_PLATFORM_VULKAN_DISPLAY_MODE_HEADLESS_ANGLE for headless mode.
>
> How to enable:
> Add
>
> ```
> use_x11=false
> angle_vulkan_display_mode="simple" # default value
> ```
>
> into args.gn, then compile with linux vulkan args.
>
> Bug: angleproject:5214
> Change-Id: I1247585b9de8b55df106aba99322281f1c183203
> Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2494320
> Commit-Queue: Jamie Madill <jmadill@chromium.org>
> Reviewed-by: Jamie Madill <jmadill@chromium.org>
> Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>

Bug: angleproject:5214
Change-Id: I3921f6cb292c86658f39e739a878baad1ef64dba
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2515327
Commit-Queue: Xiaoxuan Liu <xiaoxuan.liu@arm.com>
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>