*: move config file option oom-use-tmp-storage to sysvar

[CbcWestwolf]

What problem does this PR solve?

Issue Number: ref #33769

Problem Summary:

The option oom-use-tmp-storage has historically been a config option. But based on requirements from cloud & PM it should instead be a sysvar.

What is changed and how it works?

This does the minimum work to convert oom-use-tmp-storage to a global (cluster-wide) sysvar tidb_enable_tmp_storage_on_oom, and removes the config option (placing it in the previously deprecated list).

Check List

Tests

• Unit test (convert existing tests)
• 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

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

The TiDB configuration file option `oom-use-tmp-storage` has been replaced by the system variable `tidb_enable_tmp_storage_on_oom `. This change makes it easier to modify this setting on a cluster-wide basis.

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• morgo
• tangenta

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[sre-bot]

Code Coverage Details: https://codecov.io/github/pingcap/tidb/commit/7977ae225c5e79350a9b0178eedd938c1095a075

[CbcWestwolf]

/cc qw4990

[CbcWestwolf]

/run-all-test

[xiongjiwei]

/merge

[ti-chi-bot]

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

Commit hash: 3609a21

[CbcWestwolf]

/run-all-tests

[ti-chi-bot]

@CbcWestwolf: Your PR was out of date, I have automatically updated it for you.

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