I have already done a preliminary review for you, and I hope to help you do a better job.

Based on the pull request description and the diff, it appears that this change adds support for batch merge for mysql-test if the PR title specifies a tidb-test PR number. This is achieved by calling a new method checkoutSupportBatch instead of the existing checkout method.

Potential problems:

• It's not clear from the pull request description how the batch merge works and what the expected behavior is.
• The new method checkoutSupportBatch is not defined in the pull request, so it's unclear if it has been properly implemented and tested.
• It's unclear if there are any potential performance or stability issues with implementing batch merge.

Fixing suggestions:

• The pull request description should provide more information on how the batch merge works and what the expected behavior is. This will help reviewers understand the purpose of the change and ensure that it's properly implemented.
• The code for the new method checkoutSupportBatch should be included in the pull request so that reviewers can properly assess the implementation and provide feedback.
• It would be useful to include any performance or stability tests that were conducted to ensure that the batch merge implementation is robust.

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: wuhuizuo

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

The pull request process is described here