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>