[window function] add cume_dist implementation

[jimexist]

Which issue does this PR close?

add cume_dist implementation

Related #667

Rationale for this change

What changes are included in this PR?

Are there any user-facing changes?

[alamb]

Thanks @jimexist -- looks great to me

I also spot checked some other queries with postgres and datafusion and all looks good:

Postgres:

alamb=# select * from arr;
 x | y
---+----
 1 | 10
 1 | 11
 1 |  3
 1 |  6
 2 | 20
 1 |  3
(6 rows)


alamb=# select x, cume_dist() over (partition by x order by y) from arr;
 x | cume_dist
---+-----------
 1 |       0.4
 1 |       0.4
 1 |       0.6
 1 |       0.8
 1 |         1
 2 |         1
(6 rows)

DataFusion

echo "1,10" > /tmp/arr.csv
echo "1,11" >> /tmp/arr.csv
echo "1,3" >> /tmp/arr.csv
echo "1,6" >> /tmp/arr.csv
echo "2,20" >> /tmp/arr.csv
echo "1,3" >> /tmp/arr.csv

cargo run -p datafusion-cli

> CREATE EXTERNAL TABLE arr(x int, y int)
STORED AS CSV
LOCATION '/tmp/arr.csv';
0 rows in set. Query took 0.000 seconds.
> 
> 
select * from arr;
+---+----+
| x | y  |
+---+----+
| 1 | 10 |
| 1 | 11 |
| 1 | 3  |
| 1 | 6  |
| 2 | 20 |
| 1 | 3  |
+---+----+
6 rows in set. Query took 0.010 seconds.
> select x, cume_dist() over (partition by x order by y) from arr;
+---+-------------+
| x | CUME_DIST() |
+---+-------------+
| 1 | 0.4         |
| 1 | 0.4         |
| 1 | 0.6         |
| 1 | 0.8         |
| 1 | 1           |
| 2 | 1           |
+---+-------------+

[alamb]

👍