asahi: Disable tilebuffer write masking optimization

This seems to flake some dEQPs due to some kind of race/UB (which
doesn't even always cause the dEQPs to fail due to leeway in the image
comparison, since the problem is usually just a few pixels, but it's
there).

I spent a bunch of time trying other flags/things, and almost everything
changed the bad pixel pattern randomly but nothing fixed it. Let's
revisit this one later, since it looks like a pretty deep rabbit hole.

Signed-off-by: Asahi Lina <lina@asahilina.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/22971>

src/gallium/drivers/asahi/agx_state.c

@@ -1379,7 +1379,11 @@ agx_compile_variant(struct agx_device *dev, struct agx_uncompiled_shader *so,
       uint8_t colormasks[PIPE_MAX_COLOR_BUFS] = {0};
 
       for (unsigned i = 0; i < PIPE_MAX_COLOR_BUFS; ++i) {
-         if (agx_tilebuffer_supports_mask(&tib, i)) {
+         /* TODO: Flakes some dEQPs, seems to invoke UB. Revisit later.
+          * dEQP-GLES2.functional.fragment_ops.interaction.basic_shader.77
+          * dEQP-GLES2.functional.fragment_ops.interaction.basic_shader.98
+          */
+         if (0 /* agx_tilebuffer_supports_mask(&tib, i) */) {
             colormasks[i] = key->blend.rt[i].colormask;
             opts.rt[i].colormask = BITFIELD_MASK(4);
          } else {