Implement sampler mask using uniform buffer instead of push constant

[rjodinchr]

#1202 implements reading 3D images with a sampler using the sampler mask to know whether the coordinate needs to be normalised or not.
The sampler mask is passed through the push constant. But we can have cases where we do not have enough space in the push constant for it. In that case we need to have a fallback using a uniform buffer to pass that information.

It will require to add a non-semantic instruction in the spirv-headers.