Behaviour of work-group size attributes on devices that support more or less than 3 dimensions

Both `work_group_size_hint` and `reqd_work_group_size` are specified (see 6.7.2 in the OpenCL C specification) to take three arguments. The behaviour on devices that support more or less than 3 dimensions (`CL_DEVICE_MAX_WORK_ITEM_DIMENSIONS` != 3) is unspecified.

These interact with the `CL_KERNEL_COMPILE_WORK_GROUP_SIZE` query.

Start with section 6.7.2 of the OpenCL C specification and the CL_KERNEL_COMPILE_WORK_GROUP_SIZE query. Determine the intended behavior for devices whose CL_DEVICE_MAX_WORK_ITEM_DIMENSIONS differs from three, then update the relevant specification text and any associated references or tests identified during the investigation.

Written by the indexing model from the issue text.