Investigate why Utf8View performs worse for sort with high cardinality cases and improve it.

[zhuqi-lucas]

Is your feature request related to a problem or challenge?

This is a follow-up for the comments:
#15348 (comment)

Original result:

High Cardinality Performance

Sorting Method	utf8 Time (ms)	utf8_view Time (ms)	utf8_view Improvement
merge sorted	4.6662	5.0999	-9.3% (slower)
sort merge	4.7102	5.7224	-21.5% (slower)
sort	7.0020	6.3274	9.6% faster
sort partitioned	242.99 µs	679.86 µs	-180% (much slower)

Observations

• utf8_view performs worse for high cardinality cases:
  • merge sorted is 9.3% slower.
  • sort merge is 21.5% slower.
  • sort partitioned is 180% slower, a drastic drop.
• However, utf8_view still improves the sort method by 9.6%, likely due to reduced string operations.

We need to investigate why Utf8View performs worse for high cardinality cases and improve it.

Describe the solution you'd like

No response

Describe alternatives you've considered

No response

Additional context

No response

[zhuqi-lucas]

Latest testing result:

Benchmark	utf8 Time	utf8_view Time	Change (%)	Performance
merge sorted utf8 low cardinality	3.0828 ms	2.5903 ms	-16.0%	Improved
sort merge utf8 low cardinality	3.1103 ms	2.6354 ms	-15.3%	Improved
sort utf8 low cardinality	4.5160 ms	3.9261 ms	-13.1%	Improved
sort partitioned utf8 low cardinality	193.02 µs	190.20 µs	-1.5%	Improved
merge sorted utf8 high cardinality	4.5441 ms	3.9072 ms	-14.0%	Improved
sort merge utf8 high cardinality	4.6552 ms	4.2851 ms	-8.0%	Improved
sort utf8 high cardinality	5.3901 ms	4.5989 ms	-14.7%	Improved
sort partitioned utf8 high cardinality	223.88 µs	2.6200 ms	+1070.0%	Regressed
merge sorted utf8 tuple	10.669 ms	13.209 ms	+23.8%	Regressed
sort merge utf8 tuple	13.204 ms	15.009 ms	+13.7%	Regressed
sort utf8 tuple	10.280 ms	10.098 ms	-1.8%	Improved
sort partitioned utf8 tuple	3.2097 ms	3.5555 ms	+10.8%	Regressed
merge sorted mixed tuple	9.2576 ms	10.770 ms	+16.3%	Regressed
sort merge mixed tuple	10.520 ms	11.871 ms	+12.8%	Regressed
sort mixed tuple	9.4906 ms	8.7883 ms	-7.4%	Improved
sort partitioned mixed tuple	2.4459 ms	3.2249 ms	+31.9%	Regressed

[LSUDOKO]

take