sheet: Use buffer status on first display to prevent race in testing

Allows us to wait for indexing to finish during testing without
needing to sleep to avoid matching the initial status.

app/sheet.c

@@ -695,6 +695,8 @@ int ZSV_MAIN_FUNC(ZSV_COMMAND)(int argc, const char *argv[], struct zsv_opts *op
   cbreak();
   set_escdelay(30);
   struct zsvsheet_display_dimensions display_dims = get_display_dimensions(1, 1);
+  if (current_ui_buffer->status)
+    zsvsheet_priv_set_status(&display_dims, 1, current_ui_buffer->status);
   display_buffer_subtable(current_ui_buffer, header_span, &display_dims);
 
   zsvsheet_register_builtin_procedures();

app/sheet/read-data.c

@@ -235,12 +235,7 @@ static void *get_data_index(void *gdi) {
   pthread_mutex_unlock(&uib->mutex);
 
   char *ui_status;
-  /* I think there was a race between this print and a "? for help" which causes
-   * ci to fail. Once read-file is called the main thread displays its contents
-   * and this thread indexes the file. There is no synchronisation between the
-   * two so the status we end up with is random.
-   */
-  // asprintf(&ui_status, "%s(building index) ", old_ui_status ? old_ui_status : "");
+  asprintf(&ui_status, "%s(building index) ", old_ui_status ? old_ui_status : "");
 
   pthread_mutex_lock(&uib->mutex);
   uib->status = ui_status;