Fix encode/decode mismatches for supertx + delta-q

This fixes the following mismatch bugs:
* At the bitstream level, the decoder would not read the delta_qindex
  information for supertx blocks, but the encoder always sent it,
  leading to the encoder and decoder becoming misaligned.
  The delta_qindex information is still required for supertx blocks,
  so change the decoder to read it.
* In addition, the quantizer was not properly adjusted for supertx
  blocks at the decoder. We copy the quantizer setup code from
  non-supertx blocks.

Since this does not change the encoder, it should not have any
quality impact.

Change-Id: I9a0f79c3aa66f2a5a353821e2a6f3b526636e7b4

av1/decoder/decodeframe.c

@@ -2151,6 +2151,25 @@ static void decode_partition(AV1Decoder *const pbi, MACROBLOCKD *const xd,
 
     set_segment_id_supertx(cm, mi_row, mi_col, bsize);
 
+#if CONFIG_DELTA_Q
+    if (cm->delta_q_present_flag) {
+      for (i = 0; i < MAX_SEGMENTS; i++) {
+        xd->plane[0].seg_dequant[i][0] =
+            av1_dc_quant(xd->current_qindex, cm->y_dc_delta_q, cm->bit_depth);
+        xd->plane[0].seg_dequant[i][1] =
+            av1_ac_quant(xd->current_qindex, 0, cm->bit_depth);
+        xd->plane[1].seg_dequant[i][0] =
+            av1_dc_quant(xd->current_qindex, cm->uv_dc_delta_q, cm->bit_depth);
+        xd->plane[1].seg_dequant[i][1] =
+            av1_ac_quant(xd->current_qindex, cm->uv_ac_delta_q, cm->bit_depth);
+        xd->plane[2].seg_dequant[i][0] =
+            av1_dc_quant(xd->current_qindex, cm->uv_dc_delta_q, cm->bit_depth);
+        xd->plane[2].seg_dequant[i][1] =
+            av1_ac_quant(xd->current_qindex, cm->uv_ac_delta_q, cm->bit_depth);
+      }
+    }
+#endif
+
     xd->mi = cm->mi_grid_visible + offset;
     xd->mi[0] = cm->mi + offset;
     set_mi_row_col(xd, tile, mi_row, mi_size_high[bsize], mi_col,

av1/decoder/decodemv.c

@@ -1987,17 +1987,22 @@ static void read_inter_frame_mode_info(AV1Decoder *const pbi,
   mbmi->mv[1].as_int = 0;
   mbmi->segment_id = read_inter_segment_id(cm, xd, mi_row, mi_col, r);
 #if CONFIG_SUPERTX
-  if (!supertx_enabled) {
+  if (!supertx_enabled)
 #endif  // CONFIG_SUPERTX
     mbmi->skip = read_skip(cm, xd, mbmi->segment_id, r);
+
 #if CONFIG_DELTA_Q
-    if (cm->delta_q_present_flag) {
-      xd->current_qindex =
-          xd->prev_qindex +
-          read_delta_qindex(cm, xd, r, mbmi, mi_col, mi_row) * cm->delta_q_res;
-      xd->prev_qindex = xd->current_qindex;
-    }
+  if (cm->delta_q_present_flag) {
+    xd->current_qindex =
+        xd->prev_qindex +
+        read_delta_qindex(cm, xd, r, mbmi, mi_col, mi_row) * cm->delta_q_res;
+    xd->prev_qindex = xd->current_qindex;
+  }
 #endif
+
+#if CONFIG_SUPERTX
+  if (!supertx_enabled) {
+#endif  // CONFIG_SUPERTX
     inter_block = read_is_inter_block(cm, xd, mbmi->segment_id, r);
 
 #if CONFIG_VAR_TX