This reverts commit cbbaf76b.

Reason for revert: Suspecting this breaks the fuchsia_x64 bot WebGL
tests.

Ex: 
https://chromium-review.googlesource.com/c/chromium/src/+/2904812

Original change's description:
> [Vulkan] Add DisplayVkNull
>
> Currently all DisplayVk implementations depend on VK_KHR_swapchain and
> VK_KHR_surface extensions. When running Chromium on Fuchsia these
> extensions are never used (content is shown on the screen using
> ImagePipe API without dependency on swapchain). ANGLE still depended
> on these extensions for DisplayVkFuchsia.
> This CL adds DisplayVkNull, which allows to run ANGLE without dependency
> on swapchain. It's usable only offscreen and cannot present content on
> a surface.
>
> Bug: chromium:1203879
> Change-Id: I4d1307060967ffa68877c4300ea4d5590eeb2152
> Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2861313
> Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>
> Reviewed-by: Jamie Madill <jmadill@chromium.org>
> Commit-Queue: Jamie Madill <jmadill@chromium.org>

Bug: chromium:1203879
Change-Id: I6701ffff48fcb925f387e63b356d2d5cf360ea7e
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2904183Reviewed-by: Geoff Lang <geofflang@chromium.org>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Commit-Queue: Jamie Madill <jmadill@chromium.org>