free tile_thread task_idx_to_sby_and_tile_idx

Fixes emmory leak with asan seen with 'dav1d --tilethreads 2 ...'

src/decode.c

@@ -2255,6 +2255,7 @@ int dav1d_decode_frame(Dav1dFrameContext *const f) {
 
     if (f->n_tc > 1) {
         if (f->frame_hdr.tiling.cols * f->sbh > f->tile_thread.titsati_sz) {
+            freep(&f->tile_thread.task_idx_to_sby_and_tile_idx);
             f->tile_thread.task_idx_to_sby_and_tile_idx =
                 malloc(sizeof(*f->tile_thread.task_idx_to_sby_and_tile_idx) *
                        f->frame_hdr.tiling.cols * f->sbh);

src/lib.c

@@ -267,6 +267,7 @@ void dav1d_close(Dav1dContext **const c_out) {
             pthread_mutex_destroy(&f->tile_thread.lock);
             pthread_cond_destroy(&f->tile_thread.cond);
             pthread_cond_destroy(&f->tile_thread.icond);
+            freep(&f->tile_thread.task_idx_to_sby_and_tile_idx);
         }
         for (int m = 0; m < f->n_tc; m++) {
             Dav1dTileContext *const t = &f->tc[m];