executor: add memory tracker for quering slow_query to avoid TiDB server oom (#33953)

[ti-srebot]

cherry-pick #33953 to release-5.2
You can switch your code base to this Pull Request by using git-extras:

# In tidb repo:
git pr https://github.com/pingcap/tidb/pull/33959

After apply modifications, you can push your change to this PR via:

git push git@github.com:ti-srebot/tidb.git pr/33959:release-5.2-f988f5455049

---

What problem does this PR solve?

Issue Number: close #33893

What is changed and how it works?

Add memory tracker for slow query.

Check List

Tests

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

Release note

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None

[ti-chi-bot]

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[ti-srebot]

/run-all-tests

[ti-srebot]

@crazycs520 you're already a collaborator in bot's repo.