executor: Optimize slow log parsing's splitByColon function (#54630)

[ti-chi-bot]

This is an automated cherry-pick of #54630

What problem does this PR solve?

Issue Number: close #54538

Problem Summary:

What changed and how does it work?

Replace regexp matching with simple string comparison operations. Besides, previously, ":=" inside "{}" are not handled correctly, fix it in this PR also.
In local mannual test, performance will improve about 10x, from 24s to 2.2s for the following sql:
SELECT Digest, Query, Conn_ID, (UNIX_TIMESTAMP(Time) + 0E0) AS timestamp, Query_time, Mem_max, Process_keys FROM `INFORMATION_SCHEMA`.`CLUSTER_SLOW_QUERY` WHERE Time BETWEEN FROM_UNIXTIME(1720471890) AND FROM_UNIXTIME(1720515091) ORDER BY Query_time DESC LIMIT 100;

Check List

Tests

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

  • I checked and no code files have been changed.

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

Please refer to Release Notes Language Style Guide to write a quality release note.

None

[codecov]

Codecov Report

Attention: Patch coverage is 89.04110% with 8 lines in your changes missing coverage. Please review.

Please upload report for BASE (release-7.5@7497458). Learn more about missing BASE report.

Additional details and impacted files

@@               Coverage Diff                @@
##             release-7.5     #55795   +/-   ##
================================================
  Coverage               ?   72.0136%           
================================================
  Files                  ?       1413           
  Lines                  ?     411833           
  Branches               ?          0           
================================================
  Hits                   ?     296576           
  Misses                 ?      95368           
  Partials               ?      19889           

Flag	Coverage Δ
unit	72.0136% <89.0411%> (?)

Flags with carried forward coverage won't be shown. Click here to find out more.

Components	Coverage Δ
dumpling	52.9400% <0.0000%> (?)
parser	∅ <0.0000%> (?)
br	53.5268% <0.0000%> (?)

[windtalker]

LGTM

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: guo-shaoge, windtalker

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 [guo-shaoge,windtalker]

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:

• 2024-09-03 06:55:29.302600673 +0000 UTC m=+341053.820653579: ☑️ agreed by windtalker.
• 2024-09-03 08:04:58.313227738 +0000 UTC m=+345222.831280663: ☑️ agreed by guo-shaoge.