Miss data shuffle between mpp window functions

[LittleFall]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

see #35256 (comment)

MySQL [test]> explain select row_number() over w2, row_number() over w1 from t1 window w2 as (order by c1), w1 as (partition by c1);
+--------------------------------------+----------+--------------+---------------+-----------------------------------------------------------------------------------------------+
| id                                   | estRows  | task         | access object | operator info                                                                                 |
+--------------------------------------+----------+--------------+---------------+-----------------------------------------------------------------------------------------------+
| Projection_9                         | 10000.00 | root         |               | Column#6, Column#5                                                                            |
| └─TableReader_22                     | 10000.00 | root         |               | data:ExchangeSender_21                                                                        |
|   └─ExchangeSender_21                | 10000.00 | mpp[tiflash] |               | ExchangeType: PassThrough                                                                     |
|     └─Window_10                      | 10000.00 | mpp[tiflash] |               | row_number()->Column#6 over(order by test.t1.c1 rows between current row and current row)     |
|       └─Window_12                    | 10000.00 | mpp[tiflash] |               | row_number()->Column#5 over(partition by test.t1.c1 rows between current row and current row) |
|         └─Sort_17                    | 10000.00 | mpp[tiflash] |               | test.t1.c1                                                                                    |
|           └─ExchangeReceiver_16      | 10000.00 | mpp[tiflash] |               |                                                                                               |
|             └─ExchangeSender_15      | 10000.00 | mpp[tiflash] |               | ExchangeType: HashPartition, Hash Cols: [name: test.t1.c1, collate: binary]                   |
|               └─TableFullScan_14     | 10000.00 | mpp[tiflash] | table:t1      | keep order:false, stats:pseudo                                                                |
+--------------------------------------+----------+--------------+---------------+-----------------------------------------------------------------------------------------------+
9 rows in set (0.001 sec)

2. What did you expect to see? (Required)

there is an exchange in these windows

3. What did you see instead (Required)

no exchange

4. What is your TiDB version? (Required)

master

[fixdb]

w2 is a global window, which requires data to gather into a single worker. We should see a gather exchange here. It is a planner bug, please assign it to me.