dEQP-VK.api.image_clearing: Use the correct aspects for depth/stencil attachments

dEQP-VK.api.image_clearing: Use the correct aspects for depth/stencil attachments

These tests were blindly setting the aspectMask field of VkClearAttachment
to VK_IMAGE_ASPECT_DEPTH_BIT | VK_IMAGE_ASPECT_STENCIL_BIT even though the
format of the attachment may be a depth-only format.  This affects the
following tests:

dEQP-VK.api.image_clearing.clear_depth_stencil_attachment.2d_d16_unorm
dEQP-VK.api.image_clearing.clear_depth_stencil_attachment.2d_d32_sfloat
dEQP-VK.api.image_clearing.clear_depth_stencil_attachment.2d_x8_d24_unorm_pack32
dEQP-VK.api.image_clearing.partial_clear_depth_stencil_attachment.2d_d16_unorm
dEQP-VK.api.image_clearing.partial_clear_depth_stencil_attachment.2d_d32_sfloat
dEQP-VK.api.image_clearing.partial_clear_depth_stencil_attachment.2d_x8_d24_unorm_pack32

Change-Id: I7c0de07de97ae8529e429c26b1b99798cc1443a4