br: upgrade temporary system table

[MoCuishle28]

Signed-off-by: zhanggaoming gaoming.zhang@pingcap.com

What problem does this PR solve?

Issue Number: close #38785

Problem Summary:
TiDB changed mysql.user schema in higher version
e.g.,
version95 add a column User_attributes to mysql.user
version98 add a column Token_issuer to mysql.user

when restore 6.2.0 mysql.user to 6.4.0 will report :
Error: column count mismatch

What is changed and how it works?

Upgrade the backed up system tables before restoring to keep the schema same as the target cluster.

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

Manual Test

• insert record into mysql.user in v5.0.0 cluster
• run full backup
• restore to v6.4.0 cluster
• success

Release note

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

Fix a bug that caused: When restoring a low-version system table to a high-version cluster, it fails due to missing columns.

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has not been approved.

To complete the pull request process, please ask the reviewers in the list to review by filling /cc @reviewer in the comment.
After your PR has acquired the required number of LGTMs, you can assign this pull request to the committer in the list by filling /assign @committer in the comment to help you merge this pull request.

The full list of commands accepted by this bot can be found here.

Reviewer can indicate their review by submitting an approval review.
Reviewer can cancel approval by submitting a request changes review.

[MoCuishle28]

/component br

[MoCuishle28]

/run-build