core validation: extend CLEAR LOAD_OP check to new DS image layouts

core validation: extend CLEAR LOAD_OP check to new DS image layouts

Extend check for load operation vs first time use image layout to
new read-only depth stencil image layouts.

The new layouts were added in VK_KHR_maintenance2 / Vulkan 1.1
and follow similar restrictions to VK_IMAGE_LAYOUT_DEPTH_STENCIL_READ_ONLY_OPTIMAL.

Spec:

"
For any member of pAttachments with a loadOp equal to VK_ATTACHMENT_LOAD_OP_CLEAR,
 the first use of that attachment must not specify a layout equal to
VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_STENCIL_ATTACHMENT_OPTIMAL.

For any member of pAttachments with a stencilLoadOp equal to VK_ATTACHMENT_LOAD_OP_CLEAR,
the first use of that attachment must not specify a layout equal to
VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_STENCIL_READ_ONLY_OPTIMAL.
"