ddl: split add index real tikv tests (#48097)

[ti-chi-bot]

This is an automated cherry-pick of #48097

What problem does this PR solve?

Issue Number: close #48094

Problem Summary:

What is changed and how it works?

currently, test in real-tikv-test is run in serial, if there're too many test in one directory, test will run slow and delay pr merge, or even timeout

so we add 4 addindextestX into real tikv test, we will split the test later, to avoid test timeout as we will add more test later.

Check List

Tests

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

  • I checked and no code files have been changed.

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.

None

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: hawkingrei, ywqzzy

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2023-10-30 11:11:38.506287015 +0000 UTC m=+2865096.093397160: ☑️ agreed by hawkingrei.
• 2023-10-31 01:31:03.730403405 +0000 UTC m=+2916661.317513545: ☑️ agreed by ywqzzy.