This is a reland of 6073af53
with 2 changes -
1. Don't enable the extension even in nonConformant mode
2. Don't enable VK_KHR_image_format_list for swiftshader

Original change's description:
> Vulkan: Support EXT_sRGB_write_control
>
> Implement support for EXT_sRGB_write_control. This extension
> requires VK_KHR_image_format_list to be supported.
>
> The spec requires this functionality to work with glBlitFramebuffer
> as well but support for that will be added in a follow up change.
> As such, this extension is only exposed in non-conformant mode.
>
> Bug: angleproject:5075
> Tests: SRGBFramebufferTest.*Vulkan*
> Change-Id: I59b38f6cd810a3d0d67ec29f4f19c25f65f70862
> Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2617243
> Commit-Queue: Mohan Maiya <m.maiya@samsung.com>
> Reviewed-by: Jamie Madill <jmadill@chromium.org>
> Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>

Bug: angleproject:5075
Change-Id: I8e149d196a39c3c4769bfa8690792f3c53831299
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2762647Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Mohan Maiya <m.maiya@samsung.com>