Add custom border color swizzle tests

Add custom border color swizzle tests

New set of tests to check component swizzling with different border
colors, including custom border colors.

Note the tests currently suppose swizzling is applied to custom border
colors following the operation order in the "Texel Input Operations"
section.

Note that testing of opaque black and custom border colors with
non-identity swizzles is skipped unless VK_EXT_border_color_swizzle is
supported which has defined behavior for these combinations.

New tests:
dEQP-VK.pipeline.sampler.border_swizzle.*

Affected tests:
dEQP-VK.info.device_mandatory_features

Components: Vulkan
VK-GL-CTS issue: 2714

Change-Id: I5259744bbfa65db0386e94decb633b582d2fb17f