It saves addressing math, but may cause multiple loads to be done and
bcseled due to NIR not giving us good address alignment information
currently. I don't have any workloads I know of using non-const-uploaded
UBOs, so I don't have perf numbers for it
This makes us match the GLES blob's behavior, and turnip (other than being
bindful).
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4858>