nir/lower_io_arrays_to_elements: don't crash when hitting an indirect deref
crashing here is really not an option. if an indirect deref is reached, just skip it
fixes spec@arb_tessellation_shader@execution@variable-indexing.* for zink
crashing here is really not an option. if an indirect deref is reached, just skip it
fixes spec@arb_tessellation_shader@execution@variable-indexing.* for zink