Fix combined depth stencil handling in dEQP-VK.api.copy_and_blit

Fix combined depth stencil handling in dEQP-VK.api.copy_and_blit

The existing code had several bugs related to handling of combined DS
formats that manifested on implementations that support blitting of
said formats.

vk::isSupportedByFramework(VkFormat) utility function is added for
checking whether format is mappable to tcu::TextureFormat. This query
is used to filter out test cases that will always result in InternalError,
namely all cases that attempted to exercise formats with 64-bit channels.

Vulkan null driver is updated to advertise
VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BIT to allow easier testing.

Affects:

dEQP-VK.api.copy_and_blit.*

See #488
See #515

Change-Id: Ic03c523aea6a4bc9115568ec486200c53ec37d80