nir: Properly invalidate metadata in nir_lower_vec_to_movs().

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Jason Ekstrand <jason.ekstrand@intel.com>
Reviewed-by: Eduardo Lima Mitev <elima@igalia.com>
Cc: mesa-stable@lists.freedesktop.org
(cherry picked from commit bc3942e297)

src/glsl/nir/nir_lower_vec_to_movs.c

@@ -156,6 +156,11 @@ nir_lower_vec_to_movs_impl(nir_function_impl *impl)
 
    nir_foreach_block(impl, lower_vec_to_movs_block, &state);
 
+   if (state.progress) {
+      nir_metadata_preserve(impl, nir_metadata_block_index |
+                                  nir_metadata_dominance);
+   }
+
    return state.progress;
 }