This reverts commit 4b92e089.

Reason for revert: breaks "Linux MSan Tests" bot
https://ci.chromium.org/ui/p/chromium/builders/ci/Linux%20MSan%20Tests/28489/overview

Original change's description:
> Vulkan: Add support for EXT_texture_border_clamp
>
> Add support for GL_EXT_texture_border_clamp. This is implemented by
> using VK_EXT_custom_border_color.
>
> Bug: angleproject:3577
> Test: dEQP-GLES31.functional.texture.border_clamp*
> Change-Id: Ie9fa1eb5dd03b997b5ae182787641a53080a9e51
> Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2830192
> Reviewed-by: Jamie Madill <jmadill@chromium.org>
> Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>
> Commit-Queue: Mohan Maiya <m.maiya@samsung.com>

Bug: angleproject:3577, angleproject:5996
Change-Id: I6b62f1a4a43fcfe2d0df2c73de24db83606ce430
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2911533Reviewed-by: Yuly Novikov <ynovikov@chromium.org>
Commit-Queue: Yuly Novikov <ynovikov@chromium.org>