Add tests for VK_KHR_shader_subgroup_extended_types

Add tests for VK_KHR_shader_subgroup_extended_types

This change adds support for VK_KHR_shader_subgroup_extended_types by
extending the existing subgroup tests for the new types.

I've also taken the liberty to reduce the width parameter for graphics
tests from 1024 -> 256 (4x reduction) to offset for the over 2x increase
in number of formats.

Components: Vulkan

Affects:
dEQP-VK.subgroups.*int8_t
dEQP-VK.subgroups.*float16_t
dEQP-VK.subgroups.*int16_t
dEQP-VK.subgroups.*int64_t
dEQP-VK.subgroups.*8vec*
dEQP-VK.subgroups.*16vec*
dEQP-VK.subgroups.*64vec*

Change-Id: I70c4c5a0c444666648057050108043d14ce3c3c7
(cherry picked from commit 5f37b5269276244370a7ecaf282122f3423728ef)