Bootstrap produced invalid partition map

[jcjones]

For the map of

ENGINE=InnoDB AUTO_INCREMENT=35314177 DEFAULT CHARSET=utf8
 PARTITION BY RANGE (`id`)
(PARTITION `p_20200101` VALUES LESS THAN (198275340) ENGINE = InnoDB,
 PARTITION `p_20210125` VALUES LESS THAN (200086837) ENGINE = InnoDB,
 PARTITION `p_20210128` VALUES LESS THAN MAXVALUE ENGINE = InnoDB) |

we produced the output

# INFO:calculate_sql_alters:Table authz2, 83.6 hours, [33258619] - [35273169], [2014550] pos_change, [24089.703719704677]/hour
ALTER TABLE `authz2` REORGANIZE PARTITION `p_20210128` INTO (PARTITION `p_20210426` VALUES LESS THAN (35321348), PARTITION `p_20210526` VALUES LESS THAN (52665935), PARTITION `p_20210625` VALUES LESS THAN (70010521), PARTITION `p_20210725` VALUES LESS THAN MAXVALUE);

which failed to take into account the prior partitions, and was invalid.