This reverts commit 5c09c1f8.

Reason for revert: Breaks the Chrome OS build.

Original change's description:
> Add support for Linux GPU info with Vulkan backend
>
> 1. Add support for Linux GPU info with vulkan backend: for
> dev board without PCI support, try vulkan backend to get
> GPU info.
> 2. Fix getVulkanInstance() issue when loading non-exist lib:
> return NULL instance if open lib failed.
>
> Bug: angleproject:5717
> Change-Id: I03c11da25a8787496d098f6c9d6b4c53701383e4
> Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2734375
> Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>
> Reviewed-by: Jamie Madill <jmadill@chromium.org>
> Commit-Queue: Jamie Madill <jmadill@chromium.org>

Bug: angleproject:5717
Change-Id: I97a27295818371556fd09837485a9132f74748c6
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2737557
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Reviewed-by: Austin Eng <enga@chromium.org>
Commit-Queue: Austin Eng <enga@chromium.org>