Fix image validation errors in SPIR-V tests

Fix image validation errors in SPIR-V tests

A helper function for uploading images caused validation errors by
setting the image layout to SHADER_READ_ONLY_OPTIMAL regardless of the
image descriptor type.

A new parameter for defining the image layout was added to the helper
function, and tests using storage images were changed to use GENERAL
layout.

Affects:

dEQP-VK.spirv_assembly.instruction.compute.image_sampler.imageread.storage_image.*

Components: Vulkan, Framework

VK-GL-CTS issue: 1111

Change-Id: I783c87fe2dd91d65537343d1ae88e3a4f07b77c6