This reverts commit 9a839732.

Reason for revert: Crashes when libpci path fails on some desktop
platforms and the fallback path to Vulkan is taken.

Original change's description:
> Reland "Add support for Linux GPU info with Vulkan backend"
>
> This is a reland of 5c09c1f8
>
> Extra change: Add new ANGLE_HAS_VULKAN_SYSTEM_INFO compile
> variable for GetSystemInfoVulkan() in linux platform.
>
> 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: Iaaab8f512b6ec1d524d7ebb3b4252fec3cfe7dc3
> Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2739097
> Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>
> Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>
> Reviewed-by: Jamie Madill <jmadill@chromium.org>

Bug: angleproject:5717
Bug: chromium:1192586
Change-Id: I04f13fd4bf1d57a3ed510cd3bdf743066de96523
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2798394Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>
Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>