Improve the performance of length and ascii functions (#9345)

[ti-chi-bot]

This is an automated cherry-pick of #9345

What problem does this PR solve?

Issue Number: close #9344

Problem Summary:

What is changed and how it works?

Benchmark from bench_function_string.cpp

           origin         optimized
length    19794917 ns    1824123 ns 985.2%
ascii     20572895 ns    2592171 ns 693.7%

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)
• No code

Side effects

• Performance regression: Consumes more CPU
• Performance regression: Consumes more Memory
• Breaking backward compatibility

Documentation

• Affects user behaviors
• Contains syntax changes
• Contains variable changes
• Contains experimental features
• Changes MySQL compatibility

Release note

None

[xzhangxian1008]

/retest

[xzhangxian1008]

/run-all-tests

[JaySon-Huang]

/run-all-tests

[yibin87]

LGTM

[windtalker]

lgtm

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: windtalker, yibin87

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [windtalker,yibin87]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2024-09-06 06:52:49.128828779 +0000 UTC m=+600093.646881703: ☑️ agreed by yibin87.
• 2024-09-06 06:55:14.469438502 +0000 UTC m=+600238.987491428: ☑️ agreed by windtalker.