Summary
The checkpoint reserved transaction id is introduced to prevent prepared rollback that deletes the record from history store to race with checkpoint. WT-9268 has changed prepared rollback to not delete from the history store. The cleanup of the history store record is delayed to reconciliation. Therefore, the checkpoint reserved transaction id is no longer needed.

Motivation

• Does this affect any team outside of WT?
  No

• How likely is it that this use case or problem will occur?
  N/A

• If the problem does occur, what are the consequences and how severe are they?
  N/A

• Is this issue urgent?
  No

Acceptance Criteria (Definition of Done)
Remove checkpoint reserved transaction id and the stats, timing stress, and tests around it.

• Testing
  N/A

• Documentation update
  Check if we need to update any document or not.

[Optional] Suggested Solution