[Bug] window assigns error

### Search before asking

- [X] I searched in the [issues](https://github.com/apache/iotdb/issues) and found nothing similar.

### Version

操作系统：CentOS 7.9
IoTDB：1.1.1

### Describe the bug and provide the minimal reproduce step

window assigns in group by is different in same logic
### execute insert sql
`insert into root.hess.test.AK1407120700022.testdata (timestamp, epv_total, eload_total) VALUES (2592000000,1,1),(5011199999,2,2),(5011200000,3,3),(7689599999,4,4),(7689600000,5,5)`
`insert into root.hess.test.AK1407120700022.testdata (timestamp, epv_total, eload_total) VALUES (2563200000,10,10),(4982399999,20,20),(4982400000,30,30),(7660799999,40,40),(7660800000,50,50)`
### then execute query sql
`select SUM(epv_total) as pv,SUM(eload_total) as load from root.hess.**.AK1407120700022.** group by ([1970-02-28T08:00:00, 1970-05-31), 1mo , 2mo)`
`select SUM(epv_total) as pv,SUM(eload_total) as load from root.hess.**.AK1407120700022.** group by ([1970-02-28T08:00:00, 1970-05-31), 1mo , 1mo)`

### What did you expect to see?

IoTDB> select SUM(epv_total) as pv,SUM(eload_total) as load from root.hess.**.AK1407120700022.** group by ([1970-02-28T08:00:00, 1970-05-31), 1mo , 2mo)
+-----------------------------+----+----+
| Time| pv|load|
+-----------------------------+----+----+
|1970-02-28T08:00:00.000+08:00|97.0|97.0|
|1970-04-30T08:00:00.000+08:00|null|null|
+-----------------------------+----+----+
Total line number = 2
It costs 0.025s
IoTDB> select SUM(epv_total) as pv,SUM(eload_total) as load from root.hess.**.AK1407120700022.** group by ([1970-02-28T08:00:00, 1970-05-31), 1mo , 1mo)
+-----------------------------+----+----+
| Time| pv|load|
+-----------------------------+----+----+
|1970-02-28T08:00:00.000+08:00|97.0|97.0|
|1970-03-31T08:00:00.000+08:00| 5.0| 5.0|
|1970-04-30T08:00:00.000+08:00|null|null|
+-----------------------------+----+----+
Total line number = 3

### What did you see instead?


### Anything else?

_No response_

### Are you willing to submit a PR?

- [X] I'm willing to submit a PR!

Run the two provided GROUP BY queries against IoTDB 1.1.1 after inserting the listed rows, and compare the 1mo, 2mo and 1mo, 1mo results. Trace the window-assignment behavior in the query engine; done means equivalent window logic produces consistent interval assignments and the reproduction queries return the expected rows.

Written by the indexing model from the issue text.