The default valuse for GCDrainStackTargetSize and TASKQUEUE_SIZE are known statically. This is effetively dead code.

  if (FLAG_IS_DEFAULT(GCDrainStackTargetSize)) {
    FLAG_SET_ERGO(GCDrainStackTargetSize, MIN2(GCDrainStackTargetSize, TASKQUEUE_SIZE / 4));
  }