Extend dEQP-VK.api.image_clearing tests to cover layered images

Extend dEQP-VK.api.image_clearing tests to cover layered images

This change adds new variang of image clearing test cases:
	- *_multiple_layers
which use arrayed images and layered clears.

In the new tests variant both image views and clear operations
use layerCount smaller than `remaining` layers and non-zero
baseArrayLayer. It is expected that proper subset of layers
are cleared, while other layers are untouched.

All clear command variants (image, attachment), color formats
and image types are tested.

Affects: dEQP-VK.api.image_clearing

Components: Vulkan

VK-GL-CTS issue: 449

Change-Id: Ifedd393b14880697501df450b22740de76b6cd0c