nir: Don't reorder volatile intrinsics

Fixes issue with "is helper invocation" that in recent SPIR-V is mapped to
a volatile Load.  The CSE was catching the loads before they were transformed
in the new is_helper_invocation intrinsic (that is not reorderable).

Fixes: 729df14e45 ("nir: Handle volatile semantics for loading HelperInvocation builtin")
Reviewed-by: Jason Ekstrand <jason.ekstrand@collabora.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: M Henning <drawoc@darkrefraction.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/19432>
(cherry picked from commit 8ab628ab2e)

.pick_status.json

@@ -166,7 +166,7 @@
         "description": "nir: Don't reorder volatile intrinsics",
         "nominated": true,
         "nomination_type": 1,
-        "resolution": 0,
+        "resolution": 1,
         "main_sha": null,
         "because_sha": "729df14e4528b70e63332e4255571729253e9791"
     },

src/compiler/nir/nir.h

@@ -1968,6 +1968,9 @@ void nir_rewrite_image_intrinsic(nir_intrinsic_instr *instr,
 static inline bool
 nir_intrinsic_can_reorder(nir_intrinsic_instr *instr)
 {
+   if (nir_intrinsic_has_access(instr) &&
+       nir_intrinsic_access(instr) & ACCESS_VOLATILE)
+      return false;
    if (instr->intrinsic == nir_intrinsic_load_deref) {
       nir_deref_instr *deref = nir_src_as_deref(instr->src[0]);
       return nir_deref_mode_is_in_set(deref, nir_var_read_only_modes) ||