pkg/ddl: fix an issue where endkey usage issues caused index loss (#47818)

[ti-chi-bot]

This is an automated cherry-pick of #47818

What problem does this PR solve?

Issue Number: close #46306

Problem Summary:
Ref: #45679. Before this PR(#45679 ), we used [startKey, endKey] with endInclude as the table range. After this PR we used [startKey, endKey.next).
We do "add index" on a branch without #45679, then get startKey and endKey with the range [startKey, endKey].
Then we do upgrade, we will continue to "add index" in the branch with #45679. And we use [startKey, endKey).

What is changed and how it works?

If the old version upgrades to the new version, we add Next to the endKey.

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)

deploy v7.1.1+ cluster
set @@global.tidb_ddl_enable_fast_reorg = 0;
Create a table and import 3.5 million rows.

Do alter table t add index idx(a, b);, and when it backfills 700,000+ indexes, kill the cluster.
Then upgrade this cluster to master.
After upgrading successfully, do admin check index t idx

Result:

• Before this PR, we will get an error like ERROR 8223 (HY000): data inconsistency in table: t, index: idx, handle: 3572562, index-values:"" != record-values:"handle: 3572562, values: [KindString 131 KindString xxx]"
• After this PR, we get Query OK.

• 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

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[zimulala]

This PR will lead to an issue #47912. So don't merge it to this branch