Test input attachments in random descriptor sets test group

Test input attachments in random descriptor sets test group

Add support for input attachments in the random descriptor sets tests
group. This will improve test coverage and allow us to test
vkUpdateDescriptorSetWithTemplate with
VK_DESCRIPTOR_TYPE_INPUT_ATTACHMENT, which is a case known to be missing
coverage.

Note: every descriptorset_random test will get a new component in its
name with several variants.

Affected tests:
dEQP-VK.binding_model.descriptorset_random.*

Components: Vulkan
VK-GL-CTS issue: 1869

Change-Id: I64ac976f24c291884e71aafb0c058a9340b584c1