*: add a global system variable to control the memory quota for the bindCache

[Reminiscent]

…indCache

What problem does this PR solve?

Issue Number: ref #32466

Problem Summary:
add a global system variable to control the memory quota for the bindCache

What is changed and how it works?

Introduce a global-level system variable

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

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• morgo
• qw4990

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[Reminiscent]

@morgo PTAL, thanks~

[sre-bot]

Code Coverage Details: https://codecov.io/github/pingcap/tidb/commit/048deea06f523e8acafafefe7903339dfeab5f3d

[qw4990]

/merge

[ti-chi-bot]

This pull request has been accepted and is ready to merge.

Commit hash: ec9a54b

[Reminiscent]

/run-unit-test