message: remove some simplify() calls that are too slow
  it's just not worth it
diff: @@ -1634,7 +1634,7 @@ expr expr::store(const expr &idx, const expr &val) const {
  C(idx, val);
  expr array, str_idx, str_val;
  if (isStore(array, str_idx, str_val)) {
  - if ((idx == str_idx).simplify().isTrue())
  + if ((idx == str_idx).isTrue())
  return array.store(idx, val);
  } else if (isConstArray(str_val)) {
  @@ -1650,7 +1650,7 @@ expr expr::load(const expr &idx) const {
  // TODO: add support for alias analysis plugin
  expr array, str_idx, val;
  if (isStore(array, str_idx, val)) { // store(array, idx, val)
  - expr cmp = (idx == str_idx).simplify();
  + expr cmp = idx == str_idx;
  if (cmp.isTrue())
  return val;
  if (cmp.isFalse())
  