Relation between sref and sloc

I am trying to understand if the property `sref <= sloc` holds (where `<=` means subset of) and thus having `sloc & sref` in the definition of `mutordatom` is redundant.

If I think of `sref` and `sloc` as virtual an physical memory, I think the property should hold. However, it seems that on the device, `sref` can be [other things](https://registry.khronos.org/vulkan/specs/1.3/html/chap38.html#memory-model-references). Thus, I'm not completely sure if the property should also hold for those cases.

Start with the linked Vulkan memory-model references section and the definition of mutordatom, then compare the meanings of sref and sloc for the cases described there. Done means resolving whether sref is always a subset of sloc and recording whether the conjunction is redundant.

Written by the indexing model from the issue text.