Enable roundtrip for scaled formats in TCU

Enable roundtrip for scaled formats in TCU

Currently some swizzle tests attempting to use scaled formats end up
testing integer formats instead and pass even though the implementation
does not actually support the required scaled format features. This CL
adds scaled TCU TextureFormats which should behave identically to
integer formats but enable scaled VkFormats to be mapped correctly.

Affects:
dEQP-VK.texture.swizzle.*scaled*

Components: Framework, Vulkan

VK-GL-CTS issue: 1752

Change-Id: I038f0f82448f3c44af8d4fec0b6f258013d90f5e