nir: Validate nir_tex_instr::dest_type bitsize

In theory, we could also verify this against the sampler type for
sampler derefs, but there are a number of complications there:

- SPIR-V 1.4 lets you override the signedness of integer samplers
per-instruction. So the base type may not match.
- mediump/RelaxedPrecision samplers may get lowered to f16 in the
instruction or may not. So the bitsize may not match.

Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
Reviewed-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7989>

src/compiler/nir/nir_validate.c

@@ -824,6 +824,10 @@ validate_tex_instr(nir_tex_instr *instr, validate_state *state)
    }
 
    validate_dest(&instr->dest, state, 0, nir_tex_instr_dest_size(instr));
+
+   validate_assert(state,
+                   nir_alu_type_get_type_size(instr->dest_type) ==
+                   nir_dest_bit_size(instr->dest));
 }
 
 static void