tests: Lookup depth format instead of assuming
tests: Lookup depth format instead of assuming

Change-Id: Ie91eac3da51f4c26af04d69dfc124d195de84ebe

KhronosGroup/Vulkan-LoaderAndValidationLayers,KhronosGroup/Vulkan-LoaderAndValidationLayers,KhronosGroup/Vulkan-LoaderAndValidationLayers,KhronosGroup/Vulkan-LoaderAndValidationLayers