Currently RESTORE cannot properly handle restoring a table that had a non-mvcc rollback, without adding some logic to makeSimpleImportSpans.

Consider the following timeline:

1. Begin IMPORT INTO on existing table foo, ingest some data
2. Backup foo
3. Rollback IMPORT via clearRange
4. Incremental backup of foo, with a full reintroduction of foo’s span
5. RESTORE foo: the imported data leaks into the restore

• See test here. grep for “this is bad”

This occurs because 1) makeSimpleImportSpans naively includes the backup file with the imported data as part of foo's restoreSpanEntry and 2) the backups have MVCC delete history related to the rollback. This was never a problem in previous releases because offline importing data were not backed up until the import succeeded.

To address this, makeSimpleImportSpan needs to exclude backup files for a span that was later reintroduced due to a non-mvcc bulk op.

Jira issue: CRDB-19262