function: different grouping function will be resolved to a same one because expression action re-usage

[AilinKid]

Bug Report

Please answer these questions before submitting your issue. Thanks!
use tiflash pr: #7169

1. Minimal reproduce step (Required)

MySQL [test]>  select count(1),  grouping(a), grouping(b) from t group by a, b with rollup;
+----------+-------------+-------------+
| count(1) | grouping(a) | grouping(b) |
+----------+-------------+-------------+
|        1 |           0 |           0 |
|        2 |           1 |           1 |
|        2 |           0 |           0 |
|        1 |           0 |           0 |
+----------+-------------+-------------+
4 rows in set (0.072 sec)

MySQL [test]>  select count(1),  grouping(b), grouping(a) from t group by a, b with rollup;
+----------+-------------+-------------+
| count(1) | grouping(b) | grouping(a) |
+----------+-------------+-------------+
|        1 |           0 |           0 |
|        2 |           1 |           1 |
|        1 |           0 |           0 |
|        2 |           1 |           1 |
+----------+-------------+-------------+
4 rows in set (0.063 sec)

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

MySQL [test]>  select count(1),  grouping(a), grouping(b) from t group by a, b with rollup;
+----------+-------------+-------------+
| count(1) | grouping(a) | grouping(b) |
+----------+-------------+-------------+
|        1 |           0 |           0 |
|        2 |           1 |           1 |
|        2 |           0 |           1 |
|        1 |           0 |           0 |
+----------+-------------+-------------+
4 rows in set (0.072 sec)

MySQL [test]>  select count(1),  grouping(b), grouping(a) from t group by a, b with rollup;
+----------+-------------+-------------+
| count(1) | grouping(b) | grouping(a) |
+----------+-------------+-------------+
|        1 |           0 |           0 |
|        2 |           1 |           0 |
|        1 |           0 |           0 |
|        2 |           1 |           1 |
+----------+-------------+-------------+
4 rows in set (0.063 sec)

3. What did you see instead (Required)

as description shows.

the first encouter-ed grouping function's result will be referred to the second grouping function.

4. What is your TiFlash version? (Required)

master

[AilinKid]

/assign @AilinKid