planner: change SET_VAR behavior for non-verified vars and add some var

[winoros]

What problem does this PR solve?

Issue Number: ref #45892

Problem Summary:

What is changed and how it works?

For non-verified vars, we allow SET_VAR to change it.
Throw a warning to notify that the SET_VAR might not take effect since it's not verified.

And some more verified ones.

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

Merging #47258 (dedf078) into master (3a1112b) will decrease coverage by 0.1221%.
Report is 10 commits behind head on master.
The diff coverage is 91.6666%.

Additional details and impacted files

@@               Coverage Diff                @@
##             master     #47258        +/-   ##
================================================
- Coverage   72.9411%   72.8190%   -0.1221%     
================================================
  Files          1340       1367        +27     
  Lines        400386     408602      +8216     
================================================
+ Hits         292046     297540      +5494     
- Misses        89395      92264      +2869     
+ Partials      18945      18798       -147     

Flag	Coverage Δ
integration	33.6864% <83.3333%> (?)
unit	73.0669% <100.0000%> (+0.1258%)	⬆️

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

Components	Coverage Δ
dumpling	53.9913% <ø> (ø)
parser	84.9340% <ø> (ø)
br	48.7714% <ø> (-4.3058%)	⬇️

[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2023-09-25 12:51:00.66201275 +0000 UTC m=+279250.380354952: ☑️ agreed by qw4990.
• 2023-09-25 13:57:31.501283613 +0000 UTC m=+283241.219625831: ☑️ agreed by time-and-fate.

[yudongusa]

LGTM for the variable part. Please put more details in the issue #45892.

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: qw4990, time-and-fate, yudongusa

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 [qw4990,time-and-fate]
• sessionctx/variable/OWNERS [yudongusa]

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

[winoros]

/retest

[hawkingrei]

/retest