[groupby] fix some hotpath codes for performance

[sundy-li]

Summary

Fix some hotpath codes to improve the performance

Changelog

Fix the performance drop introduced in #550

• Improvement

Related Issues

Fixes #619

Test Plan

Performances tests

[databend-bot]

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[sundy-li]

Before

SELECT
    min(number),
    max(number),
    number % 3
FROM numbers_mt(100000000)
GROUP BY number % 3

┌─min(number)─┬─max(number)─┬─(number % 3)─┐
│           1 │    99999997 │            1 │
│           2 │    99999998 │            2 │
│           0 │    99999999 │            0 │
└─────────────┴─────────────┴──────────────┘
↑ Progress: 100.00 million rows, 800.72 MB (94.97 million rows/s., 760.48 MB/s.)
3 rows in set. Elapsed: 1.053 sec. Processed 100.00 million rows, 800.72 MB (94.97 million rows/s., 760.45 MB/s.)

After:

datafuse :)  SELECT min(number), max(number),number%3 FROM numbers_mt (100000000) GROUP BY number%3 ;

SELECT
    min(number),
    max(number),
    number % 3
FROM numbers_mt(100000000)
GROUP BY number % 3

┌─min(number)─┬─max(number)─┬─(number % 3)─┐
│           1 │    99999997 │            1 │
│           0 │    99999999 │            0 │
│           2 │    99999998 │            2 │
└─────────────┴─────────────┴──────────────┘
↗ Progress: 100.00 million rows, 800.72 MB (220.50 million rows/s., 1.77 GB/s.)
3 rows in set. Elapsed: 0.454 sec. Processed 100.00 million rows, 800.72 MB (220.48 million rows/s., 1.77 GB/s.)

cc @lideen999