Signed-off-by: Wish breezewish@outlook.com

What problem does this PR solve?

Issue Number: ref #5237

Problem Summary:

What is changed and how it works?

This PR is extracted from #6378

1. Changed dangerouslyReplaceData to be replaceData. Now it accepts an optional snapshot parameter, so that it becomes safe.

   When snapshot parameter is specified, everything data in the snapshot will be replaced, and everything after the snapshot will be kept.

   When snapshot is not specified, everything will be replaced.

   In this PR, we will not utilize this new feature. It will be used in storage: handle IngestSST using segment split #6378.

2. Segment::replaceData API does not create a ref file by itself now. The ref file is now created by the caller, in the DeltaMergeStore_Ingest.cpp.

3. Add unit tests for the new replaceData API.

4. Add randomized tests for the new replaceData. We randomly create a snapshot, and after some iterations (for example, possibly some writes) we will invoke the replaceData. We check whether the write-after-snapshot are preserved.

5. DeltaMergeStore::dangerouslyReplaceData is still preserved. It will be dropped in the next PR.

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

Release note

None